Preconception guide · for both partnersV.2.0.26.11.11

The next 90 days build the two cells that become your child.

Preparing for pregnancy, together

What to eat, how to live and what to leave behind, with every claim graded against the studies. Seven tools turn it into your own plan.

Take the 2-minute readiness check Start reading Download the PDF

74days to form one sperm

≈ 90days for an egg’s final growth

6fertile days in each cycle

400 µgfolic acid a day, starting before you try

Start here

The short answer: eggs mature over about 3 months and sperm over about 74 days [1] [2]. The habits you both keep in the 90 days before conception shape the cells that make your baby. Food, sleep, movement, heat, smoking, alcohol and body composition all leave marks on those cells, including epigenetic marks that can influence your child’s long-term health. Most of these factors can be changed, and changes made now count.

Both of you count

Half of your baby’s DNA, and its own set of epigenetic marks, comes from sperm. A father’s smoking, weight, alcohol and heat exposure before conception are linked with outcomes in children.

90 days is the window

Start at least 3 months before you try. Some changes, such as stopping anabolic steroids or reaching vitamin D sufficiency, need longer.

Food first

Most nutrients that matter for eggs and sperm come from ordinary food in realistic amounts. A few, such as folic acid for her, are worth supplementing.

How to read this guide. Every claim carries an evidence label: Strong consistent trials or large meta-analyses; Moderate good observational data or smaller trials; Emerging early, mixed or mostly animal data; Traditional long use, little or no modern testing. A link between a habit and an outcome raises or lowers the odds. It does not decide what happens to your family.

This guide is education, not medical advice. Talk to your doctor before changing medicines or starting supplements, and book a preconception appointment.

Seven tools, built into the guide

Your answers stay on this device. Use the Both, Her and Him switch at the top to show only what applies to you.

Readiness check12 habits, one score, your next three steps 90-day clockReal dates for every milestone Build your dayTap foods, fill ten nutrient targets Myth or factTen statements, call each one Caffeine counterWhere your day lands against the limit Fertile windowAn estimate from your cycle 90-day checklistFour phases, ticked off together

Tool 1 · 2 minutes

Readiness check

Twelve habits that shape egg and sperm quality. Tick what is true for you today. This is a habit check, not a fertility test.

0of 12

Starting out

Tool 2 · 30 seconds

Your 90-day clock

Pick the day you start, or started. Each milestone gets a real date, and the ring fills as the days pass.

Start date

0of 90 days

Next · 4 minWhy prepare74 days is how long one sperm takes to form. The egg’s final growth phase takes about 3 months. Both are being built right now.

1.0

Why prepare

The 90-day window and what you pass on · 4 min read

74 daysis how long one sperm takes to form. The egg’s final growth phase takes about 3 months. Both are being built right now.

Why prepare at all?

Couples often think of pregnancy as starting at conception. Biologically, it starts months earlier. The egg that ovulates next season has already begun its final growth phase, which takes roughly 3 months [2]. Every sperm takes about 74 days to form, plus around 2 weeks to mature in the epididymis [1]. What the two of you eat, how you sleep and what you smoke or drink in this window affects the quality of those cells. So does how hot the testes get.

The 90-day window

Her: about 3 months

The final growth phase of the follicle is energy-hungry. Mitochondria in the egg, oxidative stress around it, blood sugar and nutrient status all influence maturation. Moderate

Him: about 74 days

Sperm are produced continuously, so improvements show in a semen analysis about 3 months after a change. The same is true for damage: a sauna habit or a heavy drinking period shows up weeks later. Strong

What preparation can change

Fertility: time to pregnancy, regular ovulation, semen quality.
Pregnancy: lower rates of neural tube defects with folic acid [15] Strong; fewer complications linked to weight, blood sugar and smoking.
Your child’s long-term health: links with childhood asthma, leukaemia, congenital heart disease, cognitive development and metabolic health, covered in section 4.

Epigenetics: what you pass on beyond genes

Genes are the text; epigenetic marks are the highlighting that decides which parts get read. These marks, mainly DNA methylation, are partly erased at conception and then rewritten in the first weeks of life. That is why the weeks around conception matter so much.

Famine at conception leaves marks for 60 years. People conceived during the Dutch Hunger Winter of 1944 to 1945 still had lower methylation of the IGF2 growth gene six decades later. The comparison was with their unexposed brothers and sisters. The effect was specific to exposure around conception, not late pregnancy [3]. Moderate

Fathers pass on marks too. Reviews of human and animal studies show that a father’s diet, obesity, smoking, stress and chemical exposure alter sperm methylation, histones and small RNAs [4]. These travel with his DNA into the embryo. Much of the direct evidence for effects on children still comes from animals. Emerging

A father’s teenage smoking shows in his children. Children of men who started smoking before 15 had distinct DNA methylation at sites linked with asthma, weight and lung function [7]. They also had lower lung function in adulthood [8]. Moderate

Paternal weight matters. Obesity in fathers is associated with lower sperm quality, more DNA fragmentation and metabolic changes in offspring [6]. In animal studies, exercise and diet changes before conception reduced these effects [5]. Emerging

What the evidence does not show. No diet can promise a particular outcome, and epigenetic marks are not destiny. Children are shaped by pregnancy, birth, feeding, environment and love as well. Preparation shifts the odds in your favour; it is never a test you can fail.

Tool 4 · 2 minutes

Myth or fact

Ten statements couples hear all the time. Call each one before you see the answer.

10 statements

Next · 4 minThe daily foundations30 kcal per kg of lean mass a day. Below that, the brain can switch ovulation off, even at a normal weight.

2.0

The daily foundations

Training, energy, macros, body clock, stress · 4 min read

30 kcalper kg of lean mass a day. Below that, the brain can switch ovulation off, even at a normal weight.

Before any single nutrient, five foundations decide most of the result. They are enough energy, the right macronutrients, regular movement and training, a steady body clock, and manageable stress.

1. Train: strength and movement Moderate

What the research shows

In randomised trials, structured exercise improved sperm concentration, motility and morphology, and was linked with higher pregnancy and live birth rates [40]. Recreational activity helps semen quality, while elite volumes and long cycling may harm it [41]. In women, very high-intensity training and short sleep are linked with lower fertility, while moderate activity is not [42].

What to do

Strength training 2 to 4 sessions a week, 45 to 60 minutes. Schedule hard sessions in the first part of the day, when cortisol naturally peaks.
Cardio 150 to 300 minutes a week moderate, or 75 to 150 minutes vigorous [49]. Mostly moderate, steady work.
Steps 7,000 to 10,000 a day. Stand and walk for 2 to 3 minutes every 30 to 60 minutes of sitting: it also keeps the testes cooler.
Evenings are for gentle movement: walks, mobility, yoga.

Her: if your cycles become irregular or stop, reduce training volume and increase food before anything else. Him: if you cycle more than 5 hours a week, use a cut-out saddle and take breaks.

2. Eat enough: energy availability Strong

Reproduction is expensive, and the brain switches it off when energy is short. Low energy availability from under-eating, over-training or both is the main trigger of functional hypothalamic amenorrhoea, where ovulation stops. Clinicians use 30 kcal per kg of fat-free mass a day as the minimum [43]. About 45 kcal/kg is widely used as the target for full health. In men, long or deep deficits lower testosterone and sperm production.

No aggressive diets while preparing. Reach body-composition goals on as many calories as possible, creating any deficit by moving more rather than eating less.
Calorie needs depend on your own height, weight, body fat and activity, not one number per sex. Use the body-fat and calorie calculators in the WITH ME tools to set yours.
If you carry extra weight, a modest deficit through steps and training is enough. In PCOS, guidelines support even 5 to 10% weight loss to improve cycles [52].
Very low body fat in either partner, and obesity in either partner, are both linked with poorer fertility and offspring outcomes [32] [6].

3. Build the plate: macronutrients

Macro	Target	Best sources	Why it matters	Evidence
Protein	1.2 to 1.6 g/kg a day; 1.6 to 2.2 g/kg if training hard	Eggs, fish, poultry, yogurt, lentils, beans, tofu	Hormones, eggs, sperm, muscle. More plant protein in place of some animal protein was linked with lower ovulatory infertility [29]	Moderate
Carbohydrate	Mostly high-fibre, low-glycaemic; place more around training	Oats, quinoa, potatoes, rice, fruit, legumes, sourdough	Steady blood sugar and insulin support ovulation; lower dietary glycaemic load was part of the pattern linked with lower ovulatory infertility [29]	Moderate
Fat	25 to 35% of energy	Olive oil, oily fish, nuts, seeds, avocado, eggs	Sex hormones are made from cholesterol; omega-3 builds cell membranes. Each 2% of energy from trans fat instead of carbohydrate was linked with 73% higher ovulatory infertility [28]	Moderate
Fibre	30 g or more a day	Vegetables, legumes, whole grains, berries, seeds	Blood sugar control, oestrogen clearance through the gut, gut microbiome	Moderate
Water	About 2.0 L (her) and 2.5 L (him) a day from all sources	Water, herbal tea, food	Semen volume, cervical fluid, energy	Emerging

Front-load your day. Make the first meals the largest, rich in protein, healthy fats, complex carbohydrates and fibre. Let meals get smaller towards the evening. A Mediterranean-style pattern is the one most consistently linked with better semen quality [19]. It is built on vegetables, fruit, fish, legumes, nuts, whole grains and olive oil.

4. Keep the body clock steady: circadian rhythm Moderate

Reproductive hormones follow a 24-hour rhythm. Irregular sleep, later bedtimes and too little sleep are linked with lower fecundability in some cohorts, though not all [42] [45]. Night work in women and non-daytime work in men were linked with slightly higher miscarriage rates in a large North American cohort [46]. Men’s sleep duration is also associated with time to pregnancy [44].

Morning daylight outdoors for 10 to 20 minutes within an hour of waking.
The same sleep and wake time every day, within about an hour, and 7 to 9 hours in bed.
Last meal about 4 hours before sleep, so digestion is mostly finished at bedtime.
Caffeine before midday, and never coffee on an empty stomach: have it with or after breakfast.
Dim lights and screens in the last 1 to 2 hours; keep the bedroom dark and cool.
Shift workers: protect a fixed sleep block, use blackout blinds, and keep meals within a consistent window.

5. Manage stress and recover Moderate

Chronic stress is one of the three recognised triggers of functional hypothalamic amenorrhoea, alongside under-eating and over-training [43]. In men, stress alters sperm small RNAs and methylation in animal studies [4]. Trying to conceive is itself stressful, so plan for it.

Daily walks outdoors, slow breathing (5 minutes at about 6 breaths a minute), time with friends.
One fully off day a week from training.
If anxiety, low mood or relationship strain builds, speak to a counsellor or your doctor early.

6. Habits that help conception

Know the fertile window. Conception happens almost only from intercourse in the 6 days ending on ovulation day, most often in the last 3 [47]. Strong Intercourse every 1 to 2 days through that window is enough.
Track cycles with LH strips, cervical fluid and, if you like, basal body temperature (see section 5).
Lubricants: many reduce sperm motility; choose one labelled sperm-friendly, or none. Emerging
Book a preconception check-up for both of you (section 5 and 6).

Next · 26 minNutrients for eggs and sperm1 Brazil nut covers a full day of selenium, the mineral that builds the engine of a sperm cell.

3.0

Nutrients for eggs and sperm

Food first, in grams · 26 min read

1 Brazil nutcovers a full day of selenium, the mineral that builds the engine of a sperm cell.

Each card shows every role the nutrient plays, a daily target for her and for him, and realistic foods in grams. It also covers absorption, signs of low intake and the blood test, when a supplement makes sense, and the upper limit.

Daily targets follow EFSA dietary reference values [51]. Values per serving are typical and vary by product, season and country. Roles describe physiology and research findings; they are not product claims.

Tool 3 · play as long as you like

Build your day

Tap the foods you eat in a day and watch ten fertility nutrients fill up. How many targets can you reach with food alone?

Example breakfast loaded. Add the rest of your day and aim for 10 of 10.

0of 10 targets

Typical values per serving; real foods vary. Targets are daily reference values, not limits. This tool is a learning aid, not a diet record.

The 23 nutrient cards

Folate (vitamin B9)BothStrong · her: neural tube Moderate · him: food, not high-dose pills

Builds new DNA and feeds methylation, the chemistry that writes epigenetic marks onto genes. In the egg, it supports the cell divisions of maturation. In sperm, it supports DNA integrity. In the embryo, the neural tube closes 21 to 28 days after conception, usually before a pregnancy test is positive.

All its roles in the body

Cell division and tissue growth; red blood cell formation; homocysteine metabolism; amino acid synthesis; normal psychological function; lower tiredness.

Daily target

Her: 330 µg DFE a day from food, plus 400 µg folic acid a day. Start at least 1 month (ideally 3) before conception and continue until week 12. Him: 330 µg DFE a day from food.

Upper limit and excess

Upper level for folic acid from supplements and fortified foods: 1,000 µg a day. Food folate has no upper level.

Best whole foods

Food	Serving	Provides
Edamame	100 g	≈ 310 µg
Lentils, cooked	150 g	≈ 270 µg
Chickpeas, cooked	150 g	≈ 260 µg
Asparagus	100 g	≈ 150 µg
Spinach, cooked	100 g	≈ 145 µg
Broccoli	100 g	≈ 105 µg
Avocado	100 g	≈ 80 µg

Reaching it with food

150 g lentils + 100 g broccoli + 40 g spinach + half an avocado ≈ 480 µg DFE.

Absorption

Food folate is roughly half as available as folic acid (1 µg folic acid = 1.7 µg DFE). Long boiling destroys it, so steam or cook briefly. Alcohol lowers folate status.

Signs of low intake and the test

Tiredness, mouth ulcers, large red blood cells. Tests: serum or red cell folate, homocysteine.

When food is not enough

For her, the folic acid supplement is standard advice, whatever her diet. Methylfolate (5-MTHF) is a form many practitioners prefer for people with MTHFR variants; the trials that reduced neural tube defects used folic acid. Discuss the form and dose with your doctor, especially with a previous affected pregnancy, diabetes or epilepsy medication, where higher doses are prescribed. For him, a large trial of 5 mg folic acid plus 30 mg zinc did not improve semen quality or live births [17]. Food comes first.

EU-authorised wording: supplemental folate intake increases maternal folate status. Low maternal folate status is a risk factor in the development of neural tube defects in the developing foetus. The beneficial effect is obtained with 400 µg folic acid daily for at least one month before and up to three months after conception.

Vitamin B12BothModerate

Works with folate in methylation and DNA synthesis. Low maternal B12 is listed among the risk factors for neural tube defects [16]. In men, B12 supports sperm production.

All its roles in the body

Red blood cell formation; nervous system function; energy metabolism; homocysteine metabolism; immune function; lower tiredness.

Daily target

4 µg a day for both. 4.5 µg a day in pregnancy.

Upper limit and excess

No upper level set.

Best whole foods

Food	Serving	Provides
Mussels or clams, cooked	100 g	≈ 20 µg
Sardines	100 g	≈ 9 µg
Salmon	100 g	≈ 3 µg
Beef	100 g	≈ 2.5 µg
Eggs	2 (100 g)	≈ 1 µg
Milk	250 ml	≈ 1 µg

Reaching it with food

100 g salmon + 2 eggs + 250 ml milk ≈ 5 µg.

Absorption

Needs stomach acid and intrinsic factor. Metformin, acid-reducing medicines and age lower absorption.

Signs of low intake and the test

Tiredness, pins and needles, pale skin, low mood. Tests: serum B12, active B12 (holotranscobalamin), methylmalonic acid.

When food is not enough

Vegans and people on metformin or acid-reducing medicines usually need a supplement; agree the dose with your doctor after blood work.

CholineBoth, especially herModerate · need Emerging · extra in pregnancy

A methyl donor (through betaine) and a building block of every cell membrane. It is central to foetal brain development. In a small feeding trial, mothers had 930 mg or 480 mg a day in late pregnancy. Babies in the 930 mg group processed information faster [26].

All its roles in the body

Liver fat export; homocysteine metabolism; cell membranes; memory and nerve signalling; placental function.

Daily target

400 mg a day for both. 480 mg a day in pregnancy. Most women eat less than this.

Upper limit and excess

Upper level used internationally: 3.5 g a day (fishy body odour and low blood pressure above it).

Best whole foods

Food	Serving	Provides
Eggs	1 (50 g)	≈ 145 mg
Beef	150 g	≈ 170 mg
Chicken	150 g	≈ 120 mg
Salmon	120 g	≈ 110 mg
Soybeans, cooked	100 g	≈ 80 mg
Broccoli	100 g	≈ 40 mg

Reaching it with food

3 eggs at breakfast + 120 g salmon ≈ 545 mg.

Absorption

Eggs are the most practical source. Many prenatal multivitamins contain little or no choline: check the label.

Signs of low intake and the test

No routine blood test. Long-term low intake is linked to liver fat in studies.

When food is not enough

If you eat no eggs or meat, discuss a choline supplement with your doctor.

BetaineBothEmerging

Made from choline and found in foods. It recycles homocysteine back into methionine, supporting the same methylation cycle as folate and B12.

All its roles in the body

Homocysteine metabolism; cell hydration; liver function.

Daily target

No official target. Diets rich in greens and whole grains give roughly 100 to 300 mg a day or more.

Upper limit and excess

No upper level set.

Best whole foods

Food	Serving	Provides
Spinach	100 g	≈ 600 mg
Beetroot	100 g	≈ 130 mg
Quinoa, cooked	100 g	≈ 200 mg
Wholegrain wheat bread	60 g	≈ 100 mg

Reaching it with food

40 g spinach + 100 g quinoa ≈ 440 mg.

Absorption

Water-soluble; some is lost into cooking water.

Signs of low intake and the test

No routine test.

When food is not enough

Food is enough for almost everyone.

Vitamin B6BothEmerging · fertility

Needed for amino acid and homocysteine metabolism and for making neurotransmitters. Older studies link it with luteal-phase function; it is also used for nausea in pregnancy under medical advice.

All its roles in the body

Energy metabolism; red blood cell formation; immune function; hormonal activity regulation; nervous system function.

Daily target

Her: 1.6 mg a day. Him: 1.7 mg a day.

Upper limit and excess

Upper level: 12 mg a day. High doses over time can damage nerves.

Best whole foods

Food	Serving	Provides
Chicken	150 g	≈ 0.8 mg
Salmon	100 g	≈ 0.6 mg
Potato	200 g	≈ 0.6 mg
Pistachios	30 g	≈ 0.5 mg
Banana	120 g	≈ 0.45 mg

Reaching it with food

150 g chicken + 200 g potato + 1 banana ≈ 1.9 mg.

Absorption

Easily absorbed from mixed diets.

Signs of low intake and the test

Cracked lips, sore tongue, low mood. Rare with varied diets.

When food is not enough

Rarely needed beyond a standard prenatal multivitamin.

Vitamin DBothModerate · association

Vitamin D receptors sit in the ovary, the womb lining and the testes. Women with sufficient vitamin D had higher live birth rates after IVF than deficient women, in pooled cohort studies [24]. Whether correcting a deficiency changes outcomes is still being tested.

All its roles in the body

Calcium absorption; bone and muscle function; immune function; cell division.

Daily target

15 µg a day intake. Blood level (25-hydroxyvitamin D) at least 50 nmol/L; many clinicians aim for 75 to 125 nmol/L.

Upper limit and excess

Upper level: 100 µg a day.

Best whole foods

Food	Serving	Provides
Salmon	100 g	≈ 10 µg
UV-exposed mushrooms	100 g	≈ 10 µg (varies)
Sardines	100 g	≈ 5 µg
Eggs	2 (100 g)	≈ 2-3 µg

Reaching it with food

Food alone rarely reaches 15 µg. Sun on arms and legs for 10 to 30 minutes around midday from April to September helps. In winter at European latitudes the skin makes little.

Absorption

Fat-soluble: take with a meal containing fat.

Signs of low intake and the test

Tiredness, aching muscles, low mood, frequent infections. Test: 25(OH)D.

When food is not enough

A supplement is common from October to March. Agree the dose with your doctor based on your blood level.

Vitamin ABoth (her: caution with retinol)Strong · excess retinol risk

Guides cell differentiation in the embryo and supports sperm production in the testes. Too much preformed vitamin A (retinol) in early pregnancy can cause birth defects, so the source matters [31].

All its roles in the body

Vision; immune function; skin and mucous membranes; iron metabolism; cell specialisation.

Daily target

Her: 650 µg a day (700 µg in pregnancy). Him: 750 µg a day.

Upper limit and excess

Upper level for retinol: 3,000 µg a day. One 50 g portion of liver can exceed it.

Best whole foods

Food	Serving	Provides
Sweet potato, baked	150 g	≈ 1,400 µg (as beta-carotene)
Carrots	80 g	≈ 670 µg (as beta-carotene)
Spinach, cooked	100 g	≈ 470 µg (as beta-carotene)
Eggs	2 (100 g)	≈ 160 µg retinol
Liver	50 g	≈ 3,000-4,700 µg retinol

Reaching it with food

150 g sweet potato covers the day from beta-carotene, which the body converts only as needed.

Absorption

Beta-carotene from cooked orange and green vegetables, eaten with fat, is the safe route.

Signs of low intake and the test

Night blindness, dry skin and eyes. Rare in Europe.

When food is not enough

Her: no high-dose retinol supplements, no fish-liver oil, and liver or pâté only as a small, occasional portion before conception and none in pregnancy. Retinoid medicines (such as isotretinoin for acne) must be stopped with your doctor’s guidance well before trying.

Vitamin EBothModerate

The main fat-soluble antioxidant in cell membranes. Sperm membranes are rich in delicate omega-3 fats that oxidise easily, and diets rich in vitamin E are linked with better semen quality [19].

All its roles in the body

Protects cells from oxidative stress; immune function.

Daily target

Her: 11 mg a day. Him: 13 mg a day.

Upper limit and excess

Upper level: 300 mg a day.

Best whole foods

Food	Serving	Provides
Sunflower seeds	30 g	≈ 10 mg
Almonds	30 g	≈ 7.7 mg
Hazelnuts	30 g	≈ 4.5 mg
Avocado	100 g	≈ 2 mg
Extra virgin olive oil	15 g	≈ 2 mg

Reaching it with food

30 g almonds + 15 g sunflower seeds + 15 g olive oil ≈ 15 mg.

Absorption

Eat with fat; nuts and seeds bring their own.

Signs of low intake and the test

Rare; nerve and muscle problems with fat malabsorption.

When food is not enough

Food is enough for most. Antioxidant combinations for men are discussed below [18].

Vitamin CBothModerate

Concentrated in seminal fluid, where it protects sperm from oxidative damage. It also triples the absorption of plant iron when eaten in the same meal.

All its roles in the body

Collagen formation; immune function; iron absorption; protects cells from oxidative stress; lower tiredness.

Daily target

Her: 95 mg a day. Him: 110 mg a day.

Upper limit and excess

No EU upper level; above about 1 g a day can upset the gut.

Best whole foods

Food	Serving	Provides
Red pepper, raw	100 g	≈ 125 mg
Strawberries	150 g	≈ 90 mg
Broccoli, steamed	100 g	≈ 60-80 mg
Orange	130 g	≈ 70 mg
Kiwi	75 g	≈ 65 mg

Reaching it with food

1 kiwi + 100 g red pepper ≈ 190 mg.

Absorption

Heat and storage destroy it; eat some raw. Pair with lentils, beans and greens.

Signs of low intake and the test

Bleeding gums, easy bruising, slow healing.

When food is not enough

Food is enough.

Vitamin K (K1 and K2)BothEmerging · no fertility trials

Activates proteins that place calcium in bone rather than blood vessels. Popular in fertility books, but there are no human fertility trials yet.

All its roles in the body

Blood clotting; bone health.

Daily target

70 µg a day (vitamin K overall).

Upper limit and excess

No upper level set.

Best whole foods

Food	Serving	Provides
Natto	30 g	≈ 280 µg (K2)
Kale, cooked	100 g	≈ 400 µg (K1)
Hard cheese	30 g	≈ 15-20 µg (K2)
Egg yolks	2	≈ 10 µg (K2)

Reaching it with food

A serving of leafy greens covers the day.

Absorption

Fat-soluble: eat greens with oil.

Signs of low intake and the test

Easy bleeding (rare).

When food is not enough

If you take blood thinners, keep vitamin K intake steady and talk to your doctor before supplementing.

ZincBoth, especially himModerate · diet Strong · pills: no benefit

Needed for sperm production, testosterone synthesis, DNA repair and egg maturation. Seminal fluid holds about 30 times more zinc than blood.

All its roles in the body

Fertility and reproduction; testosterone levels; immune function; DNA synthesis; skin, hair and nails; cognitive function.

Daily target

Her: 7.5 to 12.7 mg a day. Him: 9.4 to 16.3 mg a day. Aim for the higher end if you eat lots of whole grains and legumes.

Upper limit and excess

Upper level: 25 mg a day. Long-term high zinc lowers copper.

Best whole foods

Food	Serving	Provides
Oysters	100 g	≈ 30-90 mg (varies)
Beef	150 g	≈ 9 mg
Chicken thigh	150 g	≈ 3 mg
Pumpkin seeds	30 g	≈ 2.2 mg
Lentils, cooked	150 g	≈ 1.9 mg
Cashews	30 g	≈ 1.7 mg

Reaching it with food

150 g beef + 30 g pumpkin seeds + 2 eggs ≈ 13 mg.

Absorption

Phytates in grains and legumes block absorption. Soaking, sprouting and sourdough fermentation reduce them. High-dose iron supplements compete with zinc.

Signs of low intake and the test

Frequent infections, slow wound healing, poor taste, hair shedding. Serum zinc is an imperfect test.

When food is not enough

In a trial of 2,370 men, 30 mg zinc plus 5 mg folic acid for 6 months did not improve semen quality or live births. It slightly raised sperm DNA fragmentation and gut symptoms [17]. Supplement only to correct a documented low.

SeleniumBothModerate

Forms selenoproteins that build the sperm midpiece, the engine of motility, and activate thyroid hormone.

All its roles in the body

Spermatogenesis; thyroid function; immune function; protects cells from oxidative stress; hair and nails.

Daily target

70 µg a day for both.

Upper limit and excess

Upper level: 255 µg a day. Excess causes hair loss and brittle nails.

Best whole foods

Food	Serving	Provides
Brazil nut	1 (5 g)	≈ 50-90 µg (varies)
Tuna	100 g	≈ 80 µg
Sardines	100 g	≈ 50 µg
Mussels	100 g	≈ 90 µg
Eggs	2 (100 g)	≈ 30 µg

Reaching it with food

1 Brazil nut + 2 eggs ≈ 90 µg.

Absorption

Well absorbed. Brazil nut content varies widely: 1 or 2 a day, not a handful.

Signs of low intake and the test

No routine test; plasma selenium if needed.

When food is not enough

Food is enough for most.

IronHer especiallyModerate

Carries oxygen and supports ovulation; in a large cohort, women with higher iron intake from plant foods and supplements had lower ovulatory infertility [29]. Iron stores also need to be ready for the 40 to 50% rise in blood volume in pregnancy.

All its roles in the body

Oxygen transport; red blood cell formation; energy metabolism; cognitive function; immune function; lower tiredness.

Daily target

Her: 16 mg a day. Him: 11 mg a day.

Upper limit and excess

Follow your doctor’s dose. High doses cause constipation and nausea.

Best whole foods

Food	Serving	Provides
Mussels	100 g	≈ 6.7 mg
Lentils, cooked	150 g	≈ 5 mg
Beef	150 g	≈ 4 mg (haem)
Tofu, firm	150 g	≈ 4 mg
Spinach, cooked	100 g	≈ 3.6 mg (poorly absorbed)
Pumpkin seeds	30 g	≈ 2.5 mg

Reaching it with food

150 g lentils + 30 g pumpkin seeds + red pepper (vitamin C) + 150 g beef 2 to 3 times a week.

Absorption

Haem iron from meat and fish is absorbed far better than plant iron. Vitamin C in the same meal helps. Tea, coffee and calcium within an hour of the meal block absorption. If an iron supplement is prescribed, take it about 1 hour before dinner on an empty stomach.

Signs of low intake and the test

Tiredness, hair shedding, breathlessness, restless legs, pale skin. Tests: ferritin and full blood count.

When food is not enough

Only supplement when blood work shows low stores. Men rarely need iron, and excess iron is harmful.

IodineBoth, especially herModerate

Makes thyroid hormones, which drive the baby’s brain development before its own thyroid works. In a UK cohort, low iodine in early pregnancy was linked with lower scores in children. They were more likely to be in the lowest quarter for verbal IQ and reading [27].

All its roles in the body

Thyroid hormone production; cognitive function; energy metabolism; skin.

Daily target

150 µg a day for both. 200 µg a day in pregnancy.

Upper limit and excess

Upper level: 600 µg a day.

Best whole foods

Food	Serving	Provides
Cod	100 g	≈ 100-200 µg
Milk	250 ml	≈ 50-100 µg (varies by country)
Greek yogurt	150 g	≈ 40-70 µg
Eggs	2 (100 g)	≈ 50 µg
Iodised salt	1 g	≈ 15-35 µg (country dependent)

Reaching it with food

150 g yogurt + 2 eggs + 100 g cod twice a week + iodised salt in cooking.

Absorption

Plant-based milks are rarely fortified. Kelp and some seaweed supplements contain far too much: avoid them.

Signs of low intake and the test

Tiredness, weight gain, feeling cold, dry skin, swelling at the neck. Tests: TSH and free T4 for thyroid function.

When food is not enough

Many prenatal multivitamins provide 150 µg. With thyroid disease, supplement only on your doctor’s advice.

MagnesiumBothEmerging · fertility

Needed by more than 300 enzymes, including those that make cellular energy and regulate insulin. It supports sleep quality and muscle recovery after training.

All its roles in the body

Energy metabolism; muscle and nerve function; electrolyte balance; protein synthesis; bone health; psychological function; lower tiredness.

Daily target

Her: 300 mg a day. Him: 350 mg a day.

Upper limit and excess

Upper level for supplemental magnesium: 250 mg a day (loose stools above it).

Best whole foods

Food	Serving	Provides
Pumpkin seeds	30 g	≈ 150 mg
Black beans, cooked	150 g	≈ 90 mg
Spinach, cooked	100 g	≈ 85 mg
Almonds	30 g	≈ 80 mg
Oats	60 g	≈ 80 mg
Dark chocolate 85%	20 g	≈ 45 mg

Reaching it with food

60 g oats + 30 g pumpkin seeds + 150 g beans ≈ 320 mg.

Absorption

Better from whole foods; high-dose zinc and very high fibre can lower it slightly.

Signs of low intake and the test

Muscle cramps, poor sleep, fatigue. Serum magnesium shows only severe lows.

When food is not enough

Food first; glycinate or citrate forms are gentler on the gut if a doctor suggests a supplement.

CopperBothEmerging

Works with zinc and iron: it is part of antioxidant enzymes and helps move iron into red blood cells.

All its roles in the body

Iron transport; connective tissue; pigmentation; immune function; energy metabolism.

Daily target

Her: 1.3 mg a day. Him: 1.6 mg a day.

Upper limit and excess

Upper level: 5 mg a day.

Best whole foods

Food	Serving	Provides
Cashews	30 g	≈ 0.6 mg
Lentils, cooked	150 g	≈ 0.4 mg
Dark chocolate 85%	20 g	≈ 0.35 mg
Sesame seeds	15 g	≈ 0.6 mg

Reaching it with food

30 g cashews + 150 g lentils + 15 g sesame seeds ≈ 1.6 mg.

Absorption

High-dose zinc supplements block copper.

Signs of low intake and the test

Anaemia that does not respond to iron; rare.

When food is not enough

Food is enough.

Omega-3 (DHA and EPA)BothModerate · observational

DHA forms the membrane of the sperm tail and of the egg, and later the baby’s brain and eyes. Young men who took fish oil had larger testes, higher semen volume and more favourable reproductive hormones in a cross-sectional study [20]. Diets rich in omega-3 are linked with better semen quality [19].

All its roles in the body

Heart function; triglyceride levels; brain and eye development; inflammation balance; mood.

Daily target

250 mg EPA plus DHA a day for both; add 100 to 200 mg DHA in pregnancy. Two portions of fish a week, one of them oily.

Upper limit and excess

Up to 5 g a day of EPA plus DHA is considered safe for adults.

Best whole foods

Food	Serving	Provides
Atlantic mackerel	100 g	≈ 2.5 g
Salmon	100 g	≈ 2 g
Sardines	100 g	≈ 1.4 g
Trout	100 g	≈ 1 g
Anchovies	50 g	≈ 0.7 g
Walnuts	30 g	≈ 2.7 g ALA (converts poorly, under 10%)

Reaching it with food

120 g salmon twice a week + 100 g sardines once ≈ 850 mg a day on average.

Absorption

Take fish or algae oil with a meal. Plant ALA converts to DHA poorly.

Signs of low intake and the test

Dry skin, poor concentration. Test: omega-3 index from a finger-prick.

When food is not enough

If you eat little fish, a fish or algae oil (algae for vegans) is reasonable. Agree the dose with your doctor if you take blood thinners.

CoQ10 (ubiquinone or ubiquinol)BothModerate · IVF pregnancy rate Emerging · live birth

Powers mitochondria, the energy factories inside cells, and protects them from oxidation. The egg is the most mitochondria-dense cell in the body, and levels fall with age. In IVF trials, CoQ10 raised clinical pregnancy rates but has not yet shown a clear effect on live births [22] [23].

All its roles in the body

Cellular energy production; antioxidant protection; heart muscle function.

Daily target

No dietary target. Research doses: 200 to 600 mg a day for 2 to 3 months.

Upper limit and excess

Doses up to 1,200 mg a day have been well tolerated in trials.

Best whole foods

Food	Serving	Provides
Sardines	100 g	≈ 5-6 mg
Beef	150 g	≈ 4 mg
Chicken	150 g	≈ 2 mg
Peanuts	30 g	≈ 0.8 mg

Reaching it with food

Food gives 3 to 10 mg a day: about 50 times below research doses. This is one of the few nutrients where only a supplement reaches the studied amount.

Absorption

Fat-soluble; take with a meal. Ubiquinol is better absorbed in some people.

Signs of low intake and the test

No routine test.

When food is not enough

Discuss with your doctor, especially over 35, with low ovarian reserve or before IVF. It can lower blood pressure and interact with warfarin.

L-carnitineHimEmerging

Carries fatty acids into mitochondria for energy. It is highly concentrated in the epididymis, where sperm mature and gain motility.

All its roles in the body

Fat metabolism for energy; exercise recovery.

Daily target

No dietary target. Trials in men used about 2 g L-carnitine plus 1 g acetyl-L-carnitine a day.

Upper limit and excess

High intakes raise TMAO, a compound under study for heart risk.

Best whole foods

Food	Serving	Provides
Beef	150 g	≈ 120-150 mg
Pork	150 g	≈ 40 mg
Milk	250 ml	≈ 8 mg

Reaching it with food

Food gives 50 to 200 mg a day: well below trial doses.

Absorption

Absorbed better from food than from large supplement doses.

Signs of low intake and the test

No routine test.

When food is not enough

It appears in several antioxidant combinations for men; overall evidence for live birth is low certainty [18]. Discuss with a doctor after a semen analysis.

Lycopene and other carotenoidsBoth, especially himModerate

Lycopene is concentrated in the testes. In a 12-week trial in healthy young men, 14 mg a day improved the share of fast-swimming and normally shaped sperm [21]. Beta-carotene, lutein and cryptoxanthin are linked with better semen quality in observational studies [19].

All its roles in the body

Antioxidant protection; eye health (lutein).

Daily target

No official target. 10 to 15 mg lycopene a day matches the trial dose.

Upper limit and excess

No upper level; very high intakes can tint skin orange (harmless).

Best whole foods

Food	Serving	Provides
Tomato paste	30 g	≈ 8-9 mg
Tomato passata	100 g	≈ 10-20 mg (varies)
Watermelon	300 g	≈ 13 mg
Raw tomato	150 g	≈ 4 mg
Pink grapefruit	150 g	≈ 2 mg

Reaching it with food

A tomato sauce with 30 g paste + 100 g passata cooked in olive oil ≈ 20 mg.

Absorption

Cooking and fat increase lycopene absorption several times.

Signs of low intake and the test

No routine test.

When food is not enough

Food reaches the trial dose easily.

PolyphenolsBothEmerging

Plant compounds in berries, olive oil, cocoa, herbs and green tea that reduce oxidative stress and feed gut bacteria. Diet patterns rich in them, such as the Mediterranean diet, are linked with better semen quality [19].

All its roles in the body

Antioxidant activity; blood vessel function; gut microbiome support.

Daily target

No official target. Aim for 30 different plants a week.

Upper limit and excess

Food is safe; extracts are not studied in preconception.

Best whole foods

Food	Serving	Provides
Berries	150 g
Extra virgin olive oil	15-30 g
Dark chocolate 85%	20 g
Green tea	1-2 cups (mind the caffeine)

Reaching it with food

Berries at breakfast, olive oil on every main meal, herbs and spices daily.

Absorption

Whole foods beat isolated extracts.

Signs of low intake and the test

No test.

When food is not enough

High-dose green tea extract supplements are not advised while trying.

Protein, glycine and arginineBothModerate · protein Emerging · glycine, arginine

Protein supplies the amino acids for eggs, sperm, hormones and, later, the placenta. In a large cohort, replacing some animal protein with plant protein was linked with lower ovulatory infertility [29]. Glycine is used for collagen and supports sleep; arginine makes nitric oxide for blood flow.

All its roles in the body

Muscle mass; tissue repair; enzyme and hormone production; immune function; bone health.

Daily target

1.2 to 1.6 g per kg body weight a day; 1.6 to 2.2 g if you strength-train hard.

Upper limit and excess

High protein intakes are safe for healthy kidneys.

Best whole foods

Food	Serving	Provides
Chicken	150 g	≈ 45 g protein
Greek yogurt	200 g	≈ 20 g protein
Lentils, cooked	150 g	≈ 14 g protein
Eggs	3 (150 g)	≈ 19 g protein
Gelatin	10 g	≈ 2.2 g glycine
Pumpkin seeds	30 g	≈ 1.5 g arginine

Reaching it with food

Spread protein over 3 to 4 meals, with the largest servings earlier in the day.

Absorption

Mixed animal and plant sources give a full amino acid profile.

Signs of low intake and the test

Muscle loss, poor recovery, brittle hair and nails, frequent hunger.

When food is not enough

Protein powder is convenient but not needed. Arginine supplements are not advised with a history of cold sores or low blood pressure.

Myo-inositolHer, especially with PCOSModerate · PCOS ovulation Emerging · live birth

Helps insulin and FSH signals work inside the ovary. In women with PCOS, inositol improved ovulation and cycle regularity compared with placebo; effects on live birth are not yet clear [25].

All its roles in the body

Insulin sensitivity; cycle regularity in PCOS; mood (studied).

Daily target

No dietary target. PCOS trials used 4 g a day (2 g twice) with 400 µg folic acid.

Upper limit and excess

Above 12 g a day can cause bloating and loose stools.

Best whole foods

Food	Serving	Provides
Orange	130 g	≈ 200 mg
Cantaloupe melon	150 g	≈ 200 mg
Beans, cooked	150 g	≈ 100-300 mg
Wholegrain bread	60 g	≈ 70 mg

Reaching it with food

Diet gives about 1 g a day: below trial doses.

Absorption

Powder dissolved in water is the usual form.

Signs of low intake and the test

No test.

When food is not enough

Discuss with your doctor if you have PCOS, irregular cycles or insulin resistance.

Egg quality nutrients

Nutrient	Role	Daily target	Top 3 foods	Evidence
Folate (vitamin B9)	Methylation and DNA for maturation; neural tube	Food 330 µg DFE + 400 µg folic acid	Edamame 100 g, lentils 150 g, spinach 100 g	Strong
Choline	Membranes, methylation, foetal brain	400 mg (480 mg pregnant)	3 eggs, beef 150 g, salmon 120 g	Moderate
Vitamin B12	Partner of folate; DNA synthesis	4 µg	Mussels 100 g, sardines 100 g, salmon 100 g	Moderate
Vitamin D	Receptors in ovary and womb lining	15 µg; blood ≥ 50 nmol/L	Salmon 100 g, UV mushrooms 100 g, sardines 100 g	Moderate
Iodine	Thyroid hormone for the baby’s brain	150 µg (200 µg pregnant)	Cod 100 g, yogurt 150 g, 2 eggs	Moderate
Iron	Ovulation; stores for pregnancy	16 mg	Mussels 100 g, lentils 150 g, beef 150 g	Moderate
Omega-3 (DHA and EPA)	Egg membranes; foetal brain and eyes	250 mg EPA + DHA	Mackerel 100 g, salmon 100 g, sardines 100 g	Moderate
CoQ10 (ubiquinone or ubiquinol)	Mitochondrial energy in the egg	200-600 mg in trials (supplement only)	Sardines 100 g, beef 150 g, chicken 150 g	Moderate
Myo-inositol	Insulin and FSH signalling (PCOS)	4 g in PCOS trials	Orange 130 g, melon 150 g, beans 150 g	Moderate
Vitamin A	Embryo cell differentiation (avoid excess retinol)	650 µg; upper level 3,000 µg retinol	Sweet potato 150 g, carrots 80 g, spinach 100 g	Strong
Protein, glycine and arginine	Building blocks; hormones	1.2-1.6 g/kg	Chicken 150 g, Greek yogurt 200 g, lentils 150 g	Moderate

Sperm quality nutrients

Nutrient	Role	Daily target	Top 3 foods	Evidence
Zinc	Sperm production, testosterone, DNA repair	9.4-16.3 mg	Oysters 100 g, beef 150 g, pumpkin seeds 30 g	Moderate
Selenium	Sperm midpiece and motility	70 µg (upper level 255 µg)	1 Brazil nut, tuna 100 g, sardines 100 g	Moderate
Omega-3 (DHA and EPA)	DHA in the sperm tail	250 mg EPA + DHA	Mackerel 100 g, salmon 100 g, sardines 100 g	Moderate
Lycopene and other carotenoids	Antioxidant concentrated in testes	10-15 mg (trial: 14 mg)	Tomato paste 30 g, passata 100 g, watermelon 300 g	Moderate
Vitamin C	Protects sperm in seminal fluid	110 mg	Red pepper 100 g, strawberries 150 g, kiwi 75 g	Moderate
Vitamin E	Protects sperm membranes	13 mg	Sunflower seeds 30 g, almonds 30 g, hazelnuts 30 g	Moderate
Folate (vitamin B9)	Sperm DNA integrity	330 µg DFE from food	Edamame 100 g, lentils 150 g, chickpeas 150 g	Moderate
Vitamin B12	Sperm production; methylation	4 µg	Mussels 100 g, sardines 100 g, beef 100 g	Moderate
Vitamin D	Receptors in testes; testosterone	15 µg; blood ≥ 50 nmol/L	Salmon 100 g, UV mushrooms 100 g, sardines 100 g	Moderate
CoQ10 (ubiquinone or ubiquinol)	Mitochondrial energy for motility	200-400 mg in trials (supplement only)	Sardines 100 g, beef 150 g, chicken 150 g	Emerging
L-carnitine	Energy for sperm maturation	2 g + 1 g ALC in trials (supplement only)	Beef 150 g, pork 150 g, milk 250 ml	Emerging

Next · 9 minWhat to avoid2 saunas a week for 3 months lowered sperm count and motility in a controlled study. Everything recovered within 6 months.

4.0

What to avoid

And why it matters for your baby · 9 min read

2 saunas a weekfor 3 months lowered sperm count and motility in a controlled study. Everything recovered within 6 months.

This section is information, not blame. Most risks below are reversible, especially for sperm, which renew every 74 days. If any of these applied to you in the past, the best time to change is now.

Tool 5 · 30 seconds

Caffeine counter

Do this instead

See section 2: enough energy, steps over cutting food, strength training.

Avoid list at a glance

Habit	Affects	Possible effect on baby	Stop how long before	Evidence
Heat to the testes	Him	Indirect: lower fertilisation potential and more sperm DNA damage during exposure.	Stop at least 3 months before trying (one full sperm cycle); recovery can take up to 6 months.	Moderate
Heat to the body in early pregnancy	Her	Neural tube defects (spina bifida): pooled odds about 1.9 times higher.	From ovulation onward in every cycle you are trying, and throughout early pregnancy. Treat a fever promptly on your doctor’s advice.	Moderate
Smoking, vaping and second-hand smoke	Both	Father’s smoking before conception: childhood acute lymphoblastic leukaemia odds about 15 to 25% higher in pooled studies. Father’s teenage smoking: offspring asthma, lower lung function and obesity.	Stop now, ideally at least 3 months before trying. Keep the home and car smoke-free.	Strong · pregnancy Moderate · preconception, father
Alcohol	Both	Congenital heart disease: father drinking in the 3 months before conception about 44% higher odds, binge drinking about 52%; mother drinking about 16%. The researchers suggested men stop 6 months and women 1 year before trying.	Him: ideally 6 months, at least 3 months. Her: stop when you start trying; there is no known safe amount in pregnancy.	Moderate
Cannabis and recreational drugs	Both	Indirect through fertility; drugs in pregnancy carry direct risks to the baby.	At least 3 months for him; stop now for her.	Moderate
Anabolic steroids, SARMs and testosterone therapy (TRT)	Him	Indirect: infertility or long delays to conception.	Recovery after stopping usually takes 3 to 12 months and sometimes longer; a minority need medical treatment to restart production. Never stop prescribed TRT without your doctor: there are fertility-preserving options.	Strong
Medicines that need review	Both	Depends on the medicine.	Review every prescription and over-the-counter product with your doctor 3 or more months before trying. Do not stop anything on your own.	Strong
Caffeine above the safe limit	Her mainly	Up to 200 mg a day in pregnancy is considered safe for the foetus; that is about 2 filter coffees or 2.5 espressos.	Keep to 200 mg a day or less from the moment you start trying. Him: moderate intake (under about 400 mg) is fine.	Moderate
Ultra-processed food, trans fats and sugary drinks	Both	Indirect through fertility, blood sugar and weight.	Start now; benefits build over the 90 days.	Moderate
High-mercury fish	Both, especially her	Neurodevelopment (mercury crosses the placenta).	Avoid swordfish, shark, marlin, king mackerel and bigeye tuna now; keep tuna steaks to once a week.	Strong
Too much preformed vitamin A	Her	Congenital malformations.	From the start of trying: no high-dose retinol supplements, no fish-liver oils, liver only as a small occasional portion before conception and none once pregnant.	Strong
Plastics and endocrine disruptors	Both	Animal data show effects across generations through epigenetic marks.	Start now; most of these chemicals clear from the body within days, so changes act quickly.	Moderate · men Emerging · women
Mobile phone in the front trouser pocket	Him	Not studied.	An easy change to make now.	Emerging
Short or irregular sleep and night work	Both	Linked with slightly higher miscarriage rates with night work.	Start now.	Emerging
Extreme dieting, overtraining, very low or very high body fat	Both	Mother’s obesity before pregnancy: childhood asthma odds about 41% higher. Father’s obesity: metabolic changes in offspring (mostly animal data).	Aim for a stable, healthy body composition before trying; avoid rapid changes in the final month.	Strong · energy availability Moderate · weight and offspring

Next · 2 minFor herDay 21 to 28 after conception the neural tube closes, often before a pregnancy test is positive.

5.0

For her

Cycle, blood tests, methylation, blood sugar · 2 min read

Day 21 to 28after conception the neural tube closes, often before a pregnancy test is positive.

Track your cycle Strong

Your cycle is a vital sign. A regular cycle of 21 to 35 days, with signs of ovulation, is good news. Track:

Cycle length and period flow in an app or diary.
LH strips from a few days before you expect to ovulate: the surge comes 24 to 36 hours before ovulation.
Cervical fluid: clear, stretchy, egg-white fluid marks the most fertile days.
Basal body temperature (optional): a rise of about 0.2 to 0.5 °C after ovulation confirms it happened.

Irregular, absent or very painful periods deserve a doctor’s visit before you start trying.

Tool 6 · 30 seconds

Fertile window estimate

An estimate from your cycle length. Confirm it with LH strips and cervical fluid, because ovulation shifts from cycle to cycle.

First day of your last period

Usual cycle length, in days

Example dates shown. Enter your own.

Blood tests to discuss with your doctor

Iron status: ferritin and full blood count.
Thyroid: TSH and free T4 (and thyroid antibodies if there is a family history).
Vitamin D (25-hydroxyvitamin D), B12 and folate.
Blood sugar: fasting glucose or HbA1c, especially with PCOS or a family history of diabetes.
Immunity to rubella and chickenpox, and a sexual health screen.
A dental check: gum health matters in pregnancy.

MTHFR and methylation Emerging

MTHFR is the enzyme that turns folate into its active form. Common gene variants reduce its activity, and methylation-focused practitioners often recommend methylfolate for carriers. The neural tube defect trials used folic acid, which works for most people, and most guideline bodies do not recommend routine MTHFR testing. A homocysteine blood test gives a practical read-out of how well your methylation cycle runs. Decide on the form of folate with your doctor.

Blood sugar, PCOS and insulin Moderate

Insulin resistance disrupts ovulation, especially in PCOS. Strength training, steps after meals, protein and fibre at every meal, and fewer refined carbohydrates help. Myo-inositol is an option to discuss (see section 3) [25].

Egg quantity and age

AMH estimates how many eggs remain, not their quality, and it does not predict natural conception well on its own. Egg quality declines with age, faster after 35, which is why the habits in this guide matter more, not less, with age. If you are over 35 and not pregnant after 6 months of trying, or over 40, see a fertility specialist; otherwise, after 12 months.

Next · 2 minFor himEvery 1 to 3 days is the ejaculation rhythm that keeps sperm fresher. Saving up does not help.

6.0

For him

Semen, heat, hormones, honest supplements · 2 min read

Every 1 to 3 daysis the ejaculation rhythm that keeps sperm fresher. Saving up does not help.

Know your numbers Strong

A semen analysis is simple, inexpensive and often skipped. WHO lower reference limits [50]:

Measure	Lower reference limit
Volume	1.4 ml
Concentration	16 million per ml
Total count	39 million per ejaculate
Progressive motility	30%
Normal forms (morphology)	4%

Results vary between samples, so one low result is usually repeated. Sperm DNA fragmentation testing is worth discussing after repeated miscarriage or failed IVF. Remember the 74-day rule: a new analysis shows the effect of changes about 3 months later.

Keep the testes cool Moderate

Stop saunas and hot tubs for at least 3 months [14]. Keep laptops off your lap, wear loose underwear, break up long sitting, and take care with long rides.

Body fat, oestrogen and testosterone Moderate

Fat tissue converts testosterone into oestrogen. Higher body fat lowers testosterone and sperm quality and raises sperm DNA damage [6]. Strength training, enough protein, 7 to 9 hours of sleep and a steady, modest deficit through movement (not crash dieting) improve the balance. Exercise interventions improved sperm concentration and motility in randomised trials [40].

Testosterone, steroids and SARMs Strong

Any testosterone from outside the body, including prescribed TRT, tells the brain to stop the signals that make sperm [33]. If you use or have used them, see an andrologist before trying; recovery can take many months [34].

Ejaculation frequency Emerging

Long abstinence does not store up better sperm: DNA damage rises after several days. Ejaculating every 1 to 3 days keeps sperm fresher. For a semen analysis, labs usually ask for 2 to 7 days of abstinence.

Supplements for men: be honest about the evidence

Antioxidant supplements for subfertile men may increase live births, but the certainty is very low. The effect disappears when higher-quality trials alone are analysed [18]. A large, well-run trial of folic acid and zinc found no benefit [17]. Diet and lifestyle come first; targeted supplements are a conversation with a doctor after a semen analysis.

Check-up for him

Blood pressure, weight, waist and body fat.
Testosterone, LH and FSH if a semen analysis is abnormal or symptoms suggest low testosterone.
Vitamin D, ferritin and a metabolic panel.
Sexual health screen and a review of medicines and supplements.

Next · 2 minTraditional and AyurvedicDinacharya the Ayurvedic daily routine of early rising, a midday main meal and early sleep, lines up with modern body-clock research.

7.0

Traditional and Ayurvedic

Described, with the evidence beside it · 2 min read

Dinacharyathe Ayurvedic daily routine of early rising, a midday main meal and early sleep, lines up with modern body-clock research.

Ayurveda treats preconception (garbhadhana) as a season of preparation for both partners, built on daily routine, digestion, nourishing food and calm. Several of these ideas match modern circadian and nutrition science; specific herbs have little or no human fertility testing. Herbs are described here, not recommended.

Practice	What it is	What the evidence shows	Safety while trying	Label
Dinacharya (daily routine)	Rising early, regular meals, largest meal at midday, early light dinner, early sleep	Matches the circadian evidence in section 2: regular sleep, morning light, earlier eating	Safe	Moderate
Warm, cooked, easily digested food; spices such as ginger, cumin, turmeric	Supports digestion (agni)	Culinary amounts are safe and fit a Mediterranean-style pattern; no fertility trials	Safe in food amounts; high-dose curcumin extracts not studied	Traditional
Ghee and whole milk	Considered nourishing for reproductive tissue (shukra dhatu)	Full-fat dairy was part of the pattern linked with lower ovulatory infertility in one large cohort [29]	Safe in moderate amounts	Emerging
Ashwagandha (Withania somnifera)	Adaptogenic root used for vitality and male fertility	A small trial in men with low sperm counts reported higher sperm count and motility after 90 days [48]	Her: avoid when trying and in pregnancy. Him: discuss with a doctor (thyroid effects, rare liver injury reported)	Emerging
Shatavari (Asparagus racemosus)	Root traditionally used for female reproductive health	No human fertility trials	Not studied in preconception or pregnancy; discuss with a doctor	Traditional
Abhyanga (warm oil self-massage)	Daily oil massage for calm and circulation	Relaxation benefit plausible; no fertility data	Safe (avoid very hot oil on the scrotum)	Traditional
Intensive cleansing programmes (panchakarma, purging, long fasts)	Traditional seasonal cleanses	No evidence for fertility; fasting and purging cut energy availability	Not advised in the 3 months before trying or in pregnancy	Traditional
Seed cycling (flax and pumpkin, then sesame and sunflower)	Holistic practice to balance the cycle	No human trials; the seeds themselves are nutritious	Safe as food	Traditional

Herbal products can contain contaminants or interact with medicines. Buy only tested products and tell your doctor about everything you take.

Next · 3 minYour 90-day plan4 phases over 12 weeks: set up, build the plate, fine-tune, get ready.

8.0

Your 90-day plan

Week by week, side by side · 3 min read

4 phasesover 12 weeks: set up, build the plate, fine-tune, get ready.

9.0

Questions couples ask

Short answers · 3 min read

12 questionsthat come up in almost every preconception conversation.

How long before trying should we start preparing?

At least 3 months. Eggs mature over about 3 months and sperm form over about 74 days, so changes made now shape the cells used at conception. Start folic acid at least 1 month before, and ideally 3.

Does the father’s health affect the baby?

Yes. A father’s smoking, alcohol, weight, heat exposure and drug use before conception are linked with sperm quality and sperm epigenetic marks. They are also linked with childhood leukaemia, asthma and congenital heart disease. Most of these effects are reversible within one or two sperm cycles.

How long should men avoid saunas before conception?

At least 3 months. Regular sauna use reduced sperm count and motility in a controlled study, and full recovery took up to 6 months after stopping.

Is one glass of wine okay while trying?

For her, no amount of alcohol is known to be safe in pregnancy, and you may be pregnant before you know it. Stop when you start trying. For him, ideally stop 3 to 6 months before trying: paternal drinking before conception is linked with congenital heart disease.

Should I take folic acid or methylfolate?

Folic acid is the form used in the trials that lowered neural tube defects, and 400 µg a day suits most women. Methylfolate is an alternative many practitioners prefer for people with MTHFR variants. Agree the form and dose with your doctor.

Can supplements fix sperm quality?

Not on their own. Large trials of folic acid and zinc showed no benefit, and evidence for antioxidant mixes is very low certainty. Diet, heat avoidance, weight, sleep and stopping smoking and alcohol have more effect.

Is exercise good or bad for fertility?

Regular moderate exercise and strength training are good for both of you. Very high training volumes with too little food can stop ovulation and lower sperm quality, so eat enough to match your training.

How much caffeine is safe while trying?

For her, up to 200 mg a day, about 2 filter coffees. For him, moderate intake under about 400 mg is fine. Have coffee after food, not on an empty stomach.

Can we change our baby’s epigenetics?

You can influence the conditions in which your baby’s epigenetic marks are written. Nutrition around conception, smoking, weight and exposure to chemicals are linked with lasting marks in human studies. Nothing can promise an outcome, and much of the detail is still being researched.

Do we need to reach a perfect weight first?

No. Aim for a stable, healthy body composition and regular cycles. In PCOS, losing 5 to 10% of body weight can restore ovulation. Avoid crash diets, which can stop ovulation and lower sperm quality.

Is a vegan diet fine while trying?

It can be, with care, but treat this guidance as indicative and plan it with your doctor. Vegans commonly run low in B12, iodine, choline, DHA, iron, zinc, vitamin D and calcium. Do blood work and discuss supplements with your doctor before starting them.

When should we see a fertility specialist?

After 12 months of regular unprotected intercourse without pregnancy, or after 6 months if she is over 35. Go straight away if she is over 40 or has irregular or absent periods, endometriosis or PCOS. The same applies if he has a known sperm problem or past steroid use.

End of the guideYou have the whole picture.Go back to your readiness check and your 90-day clock, and pick your next three steps together.Open the readiness check Download the PDF

10.0

References

Studies, books and practitioners

Studies and official sources (52)

1Heller CG, Clermont Y. Spermatogenesis in man: an estimate of its duration. Science. 1963;140:184-186.
2Gougeon A. Dynamics of follicular growth in the human: a model from preliminary results. Hum Reprod. 1986;1(2):81-87.
3Heijmans BT, Tobi EW, Stein AD, et al. Persistent epigenetic differences associated with prenatal exposure to famine in humans. PNAS. 2008;105(44):17046-17049. PMID 18955703.
4Akhatova A, Jones C, Coward K, Yeste M. How do lifestyle and environmental factors influence the sperm epigenome? Effects on sperm fertilising ability, embryo development, and offspring health. Clin Epigenetics. 2025;17. PMID 39819375.
5Billah MM, Khatiwada S, Morris MJ, Maloney CA. Effects of paternal overnutrition and interventions on future generations. Int J Obes. 2022. doi:10.1038/s41366-021-01042-7.
6Raad G, Hazzouri M, Bottini S, et al. Paternal obesity: how bad is it for sperm quality and progeny health? Basic Clin Androl. 2017;27:20. doi:10.1186/s12610-017-0064-9.
7Kitaba NT, Knudsen GTM, Johannessen A, et al. Fathers’ preconception smoking and offspring DNA methylation. Clin Epigenetics. 2023;15:131. doi:10.1186/s13148-023-01540-7.
8Accordini S, et al. Prenatal and prepubertal exposures to tobacco smoke in men may cause lower lung function in future offspring: a three-generation study (ECRHS/RHINESSA). Eur Respir J. 2021. PMC8529197.
9Liu R, Zhang L, McHale CM, Hammond SK. Paternal smoking and risk of childhood acute lymphoblastic leukemia: systematic review and meta-analysis. J Oncol. 2011;2011:854584. doi:10.1155/2011/854584.
10Cao Y, Lu J, Lu J. Paternal smoking before conception and during pregnancy is associated with an increased risk of childhood acute lymphoblastic leukemia: a systematic review and meta-analysis of 17 case-control studies. 2020. PMID 31743318.
11Zhang S, Wang L, Yang T, et al. (Qin J, senior author). Parental alcohol consumption and the risk of congenital heart diseases in offspring: an updated systematic review and meta-analysis. Eur J Prev Cardiol. 2020. doi:10.1177/2047487319874530.
12Moretti ME, Bar-Oz B, Fried S, Koren G. Maternal hyperthermia and the risk for neural tube defects in offspring: systematic review and meta-analysis. Epidemiology. 2005;16(2):216-219. PMID 15703536.
13Milunsky A, Ulcickas M, Rothman KJ, et al. Maternal heat exposure and neural tube defects. JAMA. 1992;268(7):882-885.
14Garolla A, Torino M, Sartini B, et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Hum Reprod. 2013;28(4):877-885. PMID 23411620.
15De-Regil LM, Peña-Rosas JP, Fernández-Gaxiola AC, Rayco-Solon P. Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database Syst Rev. 2015;(12):CD007950. PMID 26662928.
16Arabzadeh H, Jenabi E, Masoumi SZ. Maternal factors for neural tube defects in offspring: an umbrella review. Open Med. 2024. doi:10.1515/med-2024-1061.
17Schisterman EF, Sjaarda LA, Clemons T, et al. Effect of folic acid and zinc supplementation in men on semen quality and live birth among couples undergoing infertility treatment (FAZST): a randomized clinical trial. JAMA. 2020;323(1):35-48. PMID 31910279.
18de Ligny W, Smits RM, Mackenzie-Proctor R, et al. Antioxidants for male subfertility. Cochrane Database Syst Rev. 2022;(5):CD007411. PMID 35506389.
19Salas-Huetos A, Bulló M, Salas-Salvadó J. Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Hum Reprod Update. 2017;23(4):371-389. PMID 28333357.
20Jensen TK, Priskorn L, Holmboe SA, et al. Associations of fish oil supplement use with testicular function in young men. JAMA Netw Open. 2020;3(1):e1919462. PMID 31951274.
21Williams EA, Parker M, Robinson A, Pitt S, Pacey AA. A randomized placebo-controlled trial to investigate the effect of lactolycopene on semen quality in healthy males. Eur J Nutr. 2020;59(2):825-833. doi:10.1007/s00394-019-02091-5.
22Florou P, Anagnostis P, Theocharis P, Chourdakis M, Goulis DG. Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? J Assist Reprod Genet. 2020;37(10):2377-2387. PMID 32767206.
23Lin G, Li X, Jin Yie SL, Xu L. Clinical evidence of coenzyme Q10 pretreatment for women with diminished ovarian reserve undergoing IVF/ICSI: a systematic review and meta-analysis. 2024. PMID 39129455.
24Chu J, Gallos I, Tobias A, et al. Vitamin D and assisted reproductive treatment outcome: a systematic review and meta-analysis. Hum Reprod. 2018;33(1):65-80. PMID 29149263.
25Pundir J, Psaroudakis D, Savnur P, et al. Inositol treatment of anovulation in women with polycystic ovary syndrome: a meta-analysis of randomised trials. BJOG. 2018;125(3):299-308. PMID 28544572.
26Caudill MA, Strupp BJ, Muscalu L, et al. Maternal choline supplementation during the third trimester of pregnancy improves infant information processing speed: a randomized, double-blind, controlled feeding study. FASEB J. 2018;32(4):2172-2180. PMID 29217669.
27Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from ALSPAC. Lancet. 2013;382(9889):331-337. PMID 23706508.
28Chavarro JE, Rich-Edwards JW, Rosner BA, Willett WC. Dietary fatty acid intakes and the risk of ovulatory infertility. Am J Clin Nutr. 2007;85(1):231-237.
29Chavarro JE, Rich-Edwards JW, Rosner BA, Willett WC. Diet and lifestyle in the prevention of ovulatory disorder infertility. Obstet Gynecol. 2007;110(5):1050-1058.
30EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the safety of caffeine. EFSA Journal. 2015;13(5):4102.
31EFSA Panel on Nutrition, Novel Foods and Food Allergens. Scientific opinion on the tolerable upper intake level for preformed vitamin A and β-carotene. EFSA Journal. 2024;22(6):e8814.
32Liu S, Zhou B, Wang Y, et al. Pre-pregnancy maternal weight and gestational weight gain increase the risk for childhood asthma and wheeze: an updated meta-analysis. Front Pediatr. 2020;8:134. doi:10.3389/fped.2020.00134.
33Desai A, Yassin M, Cayetano A, et al. Understanding and managing the suppression of spermatogenesis caused by testosterone replacement therapy (TRT) and anabolic-androgenic steroids (AAS). Ther Adv Urol. 2022;14. PMID 35783920.
34McBride JA, Coward RM. Recovery of spermatogenesis following testosterone replacement therapy or anabolic-androgenic steroid use. Asian J Androl. 2016;18(3):373-380. doi:10.4103/1008-682X.173938.
35Gundersen TD, Jørgensen N, Andersson AM, et al. Association between use of marijuana and male reproductive hormones and semen quality: a study among 1,215 healthy young men. Am J Epidemiol. 2015;182(6):473-481. PMID 26283092.
36Adams JA, Galloway TS, Mondal D, Esteves SC, Mathews F. Effect of mobile telephones on sperm quality: a systematic review and meta-analysis. Environ Int. 2014;70:106-112. doi:10.1016/j.envint.2014.04.015.
37Green MP, Harvey AJ, Finger BJ, Tarulli GA. Endocrine disrupting chemicals: impacts on human fertility and fecundity during the peri-conception period. Environ Res. 2021. PMID 33385395.
38Hipwell AE, Kahn LG, Factor-Litvak P, et al. Exposure to non-persistent chemicals in consumer products and fecundability: a systematic review. Hum Reprod Update. 2019;25(1):51-71. PMID 30307509.
39Mínguez-Alarcón L, Gaskins AJ. Female exposure to endocrine disrupting chemicals and fecundity: a review. Curr Opin Obstet Gynecol. 2017;29(4):202-211. PMID 28557831.
40Effects of physical activity on fertility parameters: a meta-analysis of randomized controlled trials. World J Mens Health. 2024;42(3):555-562. PMID 38164031.
41An update on the implication of physical activity on semen quality: a systematic review and meta-analysis. Arch Gynecol Obstet. 2019. doi:10.1007/s00404-019-05045-8.
42Zhao F, Hong X, Wang W, Wu J, Wang B. Effects of physical activity and sleep duration on fertility: a systematic review and meta-analysis based on prospective cohort studies. Front Public Health. 2022;10:1029469.
43Dietary and lifestyle management of functional hypothalamic amenorrhea: a comprehensive review. Nutrients. 2024;16(17):2967. PMID 39275282.
44Wise LA, Rothman KJ, Wesselink AK, et al. Male sleep duration and fecundability in a North American preconception cohort study (PRESTO). Fertil Steril. 2018. PMC5868973.
45Christensen MH, Mikkelsen EM, Wise LA, Hatch EE, Laursen ASD. The association between sleep and fecundability: a Danish preconception cohort study. Eur J Public Health. 2025;35(3):512-520. PMID 40139814.
46Preconception sleep duration, non-daytime work schedules, and incidence of spontaneous abortion: a prospective cohort study (PRESTO, 9,357 women and 2,602 male partners, 2013-2023).
47Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation: effects on the probability of conception, survival of the pregnancy, and sex of the baby. N Engl J Med. 1995;333(23):1517-1521.
48Ambiye VR, Langade D, Dongre S, Aptikar P, Kulkarni M, Dongre A. Clinical evaluation of the spermatogenic activity of the root extract of ashwagandha (Withania somnifera) in oligospermic males: a pilot study. Evid Based Complement Alternat Med. 2013;2013:571420.
49Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451-1462.
50World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th edition. Geneva: WHO; 2021.
51European Food Safety Authority. Dietary Reference Values for nutrients: summary report. EFSA Supporting Publications. 2017;14(12):e15121 (and later updates to upper levels for selenium, vitamin B6 and vitamin D).
52Teede HJ, Tay CT, Laven JSE, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Hum Reprod. 2023;38(9):1655-1679.

Books, practitioners and educational sources (15)

These shaped the structure and topics of the guide. Where their advice goes beyond the studies above, this guide follows the studies.

B1Fett R. It Starts with the Egg: How the Science of Egg Quality Can Help You Get Pregnant Naturally, Prevent Miscarriage, and Improve Your Odds in IVF. 2nd ed. Franklin Fox Publishing; 2019.
B2Nichols L. Real Food for Pregnancy: The Science and Wisdom of Optimal Prenatal Nutrition. 2018.
B3Lynch B. Dirty Genes: A Breakthrough Program to Treat the Root Cause of Illness and Optimize Your Health. HarperOne; 2018.
B4Seeking Health. Educational articles on methylation, MTHFR and preconception nutrition (seekinghealth.com).
B5Swan SH, Colino S. Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race. Scribner; 2021.
B6Chavarro JE, Willett WC, Skerrett PJ. The Fertility Diet. McGraw-Hill; 2008.
B7Hendrickson-Jack L. The Fifth Vital Sign: Master Your Cycles and Optimize Your Fertility. 2019.
B8Weschler T. Taking Charge of Your Fertility. 20th anniversary ed. William Morrow; 2015.
B9Briden L. Period Repair Manual. 2nd ed. 2017.
B10Brighten J. Beyond the Pill. HarperOne; 2019.
B11Vitti A. WomanCode. HarperOne; 2013.
B12Asprey L, Asprey D. The Better Baby Book. Wiley; 2013.
B13Norton L, Baker P. Fat Loss Forever; and Biolayne evidence-based nutrition education (biolayne.com).
B14Charaka Samhita and Ashtanga Hridaya (classical Ayurvedic texts) on preconception care (garbhadhana) and daily routine (dinacharya).
B15Leading preconception coaches, registered nutritionists and holistic and Ayurvedic practitioners: public education material reviewed for consensus and points of disagreement.

Education, not medical advice. This guide does not replace care from your doctor, midwife or fertility specialist. Talk to them before changing medicines or starting supplements, especially in pregnancy.

WITH ME NUTRITION S.R.L.

More of yourself,
available for life.

Start here

Both of you count

90 days is the window

Food first

Seven tools, built into the guide

Readiness check

Your 90-day clock

Contents

Why prepare

Why prepare at all?

The 90-day window

Her: about 3 months

Him: about 74 days

What preparation can change

Epigenetics: what you pass on beyond genes

Myth or fact

The daily foundations

1. Train: strength and movement Moderate

What the research shows

What to do

2. Eat enough: energy availability Strong

3. Build the plate: macronutrients

4. Keep the body clock steady: circadian rhythm Moderate

5. Manage stress and recover Moderate

6. Habits that help conception

Nutrients for eggs and sperm

Build your day

The 23 nutrient cards

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods

Reaching it with food

Absorption

Signs of low intake and the test

When food is not enough

All its roles in the body

Daily target

Upper limit and excess

Best whole foods