The Journal · Before Conception
Before you try: the months that count
There is a short list of things that genuinely matter before conception, and a very long list of things that do not. We would rather you spent your energy on the short one.
The preconception advice available online falls into two camps. One is a single line about folic acid. The other is a nine-part protocol involving elimination diets, extensive testing and about two hundred pounds a month of supplements.
The useful version sits much closer to the first. Here it is.
Folic acid, and why the timing is the point
UK guidance is 400 micrograms of folic acid daily, starting before you conceive and continuing until the twelfth week of pregnancy.1
The timing matters more than almost anything else here. Folic acid reduces the risk of neural tube defects such as spina bifida, and the neural tube closes within the first four weeks of pregnancy — often before a period is missed, and usually before anyone has taken a test. Which means the supplement has to already be in place. Starting it on the day of a positive test is starting late.
Some people are advised to take a higher dose of 5mg, including those with diabetes, a raised BMI, epilepsy on certain medications, sickle cell disease or thalassaemia, a previous pregnancy affected by a neural tube defect, or a family history of one. That is a prescription decision, so raise it with your GP rather than buying a high-dose product over the counter.1
Vitamin D, and iodine
Everyone in the UK is advised to consider 10 micrograms of vitamin D daily in autumn and winter, and this applies before and during pregnancy too.2,3
Iodine gets far less attention than it deserves. Adults need 140 micrograms a day, and it is essential for thyroid hormones and for a baby's brain development. The main UK sources are dairy, white fish and eggs — which means people who have moved to plant milks without checking for iodine fortification are often getting very little. Most plant milks are not fortified with iodine.4
Do not solve this with seaweed supplements or kelp tablets. They can contain enormous and unpredictable amounts of iodine, and too much is a problem for the thyroid in its own right. Food, or a pregnancy multivitamin containing iodine, is the sensible route.
The preconception supplement list, complete
- Folic acid 400µg daily — or the dose your GP has prescribed.
- Vitamin D 10µg daily.
- A pregnancy-specific multivitamin covers both, plus iodine, if you would rather take one thing. Check it contains no vitamin A as retinol, which should be avoided in pregnancy.
That is the list. Anything beyond it should be because a practitioner looked at you specifically — not because a website said fertility.
Why three months
You will see three months quoted a lot. The reasoning is reasonable: sperm take around two to three months to develop, and an egg's final maturation takes a similar stretch. So changes made now are affecting cells that will be involved in a conception a season from now.
Treat that as encouragement rather than pressure. If you are already trying, or you conceived last month, nothing has been missed — the first trimester and the whole of pregnancy remain enormously influenceable. Three months is a nice runway when you have one. It is not a qualification.
Both of you
Preconception advice is overwhelmingly addressed to women, which is odd given that sperm contribute half the genetic material and sperm quality is responsive to diet, weight, smoking, alcohol and heat over that same two-to-three-month window.
The useful version for a male partner is unglamorous and identical to general good health: a varied diet with enough vegetables and oily fish, not smoking, keeping alcohol moderate, and addressing weight if it is high. There is no supplement here we would insist on. There is quite a lot of expensive fertility-branded supplementation we would skip.
Weight, said carefully
Being significantly over or under a healthy weight can affect fertility and pregnancy, and it is reasonable to look at it if it applies. But we want to be careful, because this is the point where preconception advice most often tips into something unhelpful.
Restrictive dieting while trying to conceive is generally counterproductive — it can affect cycles, and it is a difficult thing to be doing during a period that is already emotionally demanding. The more useful frame is adding rather than removing: more vegetables, more fibre, more protein at breakfast, more walking. If weight is a genuine clinical factor, your GP is the right person to help you plan it properly.
Alcohol and caffeine
The safest position on alcohol once you are trying is none, because the earliest weeks of pregnancy happen before you know about them.1 We say that as information rather than instruction, and one drink at a wedding before you knew is not something to carry around.
Caffeine should stay under 200mg a day in pregnancy — roughly two mugs of instant coffee, or one strong filter coffee. Worth starting the taper now, since caffeine withdrawal on top of first-trimester nausea is a poor combination. Remember tea, green tea, cola and chocolate all count.5
What we would not spend money on
Broad food intolerance testing. Hair mineral analysis. Ovulation-boosting herbal blends. Expensive fertility supplement stacks with twenty-five ingredients at token doses. “Detoxes”, which have no bearing on fertility and occasionally involve genuinely unwise things.
If something is going on — irregular cycles, known PCOS or endometriosis, a year of trying without success, previous loss — then investigation is absolutely right, but the route is your GP and a fertility clinic. That is where the tests that actually change decisions live.
What we'd do this week
Buy folic acid and vitamin D, and put them next to the kettle so you actually take them. Book a GP appointment if any of the higher-dose folic acid factors apply to you. Check whether your milk has iodine in it. Then, honestly, go and enjoy your food — because eating well before pregnancy should feel like looking after yourself, and most of what is marketed at this moment does the precise opposite.
Sources & further reading
A note on what this is. This article is general information, written by registered nutritional therapists and referenced above. It is not a diagnosis and it is not a substitute for advice about you. If you are pregnant, breastfeeding, taking medication, or managing a health condition, please talk to your GP, midwife, health visitor or a registered practitioner before making changes — and always speak to them first if something is worrying you.