Preconception health: steps before trying to get pregnant
Preconception health is the health of both partners in the months before a pregnancy begins, and folic acid is the best-studied step taken during that time.
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Medically reviewed by Dr Mary Davidson, Reproductive endocrinologist, checked on
The first weeks of pregnancy, when the brain, spine and major organs form, often pass before a pregnancy is known (CDC, About folic acid, 2026; ACOG, reviewed 2025). That is why guidance on folic acid, alcohol, smoking, weight and medicines applies before conception rather than from the first appointment in pregnancy. This page sets out what US and UK guidance says about preconception health, and where the two differ.
Folic acid before pregnancy
Folic acid lowers the risk of neural tube defects, serious birth defects of the brain and spine that form in the first weeks, and it is the only form of folate shown to help prevent them (CDC, 2026). US and UK guidance agree on 400 micrograms a day and differ on when to start: at least 1 month before conception in the advice of the CDC and the US Preventive Services Task Force, and ideally 3 months before in the NHS's (USPSTF, 2023; NHS, 2026). A higher dose is a clinical decision, and the two countries name different groups for it. The amounts, the timing, who is advised more and why the window closes at 12 weeks are set out in full in the guide to folic acid before pregnancy, and what else a supplement may contain is in the guide to prenatal vitamins.
Vitamin D appears in UK guidance and not in the US sources here
The NHS lists vitamin D alongside folic acid among the supplements to consider before and while trying to conceive, and recommends 10 micrograms a day in pregnancy between early October and late March (NHS, 2026). None of the US sources on this page, the CDC, the USPSTF and ACOG, makes a separate vitamin D recommendation for this period.
US and UK guidance both advise stopping alcohol, smoking and drugs before trying
The CDC advises stopping drinking, smoking and some drug use before pregnancy, because each can cause premature birth, birth defects or infant death (CDC, Planning for pregnancy, 2025). The NHS lists not drinking alcohol, getting support to stop smoking and not using illegal drugs among the steps to take before and while trying, and notes that a GP can arrange support (NHS, Planning your pregnancy, 2026). The guide to how to get pregnant sets these steps beside the timing of sex.
Weight before pregnancy affects both conceiving and the pregnancy
The NHS states that a weight that is too low or too high can make it harder to get pregnant, and that being overweight in pregnancy raises the risk of high blood pressure, pre-eclampsia, gestational diabetes and blood clots (2026). ACOG adds that being underweight raises the risk of preterm birth and of a baby with a low birth weight. It uses the standard body mass index (BMI) categories: below 18.5 underweight, 18.5 to 24.9 normal weight, 25 to 29.9 overweight, and 30 or greater obese (reviewed 2025).
Prescribed medicines are reviewed with a doctor, not stopped
The NHS advises against stopping any prescribed medicine before discussing it with a GP or specialist, who can weigh the safest option while trying to conceive (2026). The CDC lists every medicine, supplement and vitamin among the subjects to raise with a doctor before pregnancy (2025). What that conversation covers is set out in the guide to the preconception checkup.
A male partner's health is part of preconception health
ACOG and the CDC both extend their advice to men. ACOG advises a male partner to give up smoking, alcohol and drugs before trying, because they may damage sperm (reviewed 2025), and the CDC notes that toxic substances at home and at work can harm the reproductive systems of men and women (2025). The evidence on lifestyle and semen quality is summarized in the guide to sperm health, the causes of male infertility in the guide to male fertility, and what a low sperm count means in its own guide.
Sources
- US Preventive Services Task Force. Folic Acid Supplementation to Prevent Neural Tube Defects: Preventive Medication, final recommendation statement, 1 August 2023. JAMA 2023.
- CDC. About Folic Acid, updated 10 September 2026. Planning for Pregnancy, updated 8 May 2025.
- American College of Obstetricians and Gynecologists. Good Health Before Pregnancy: Prepregnancy Care, FAQ056, reviewed October 2025.
- NHS. Vitamins, supplements and nutrition in pregnancy, reviewed 3 June 2026. Planning your pregnancy, reviewed 2 June 2026.
- Schisterman 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. JAMA 2020.
Frequently asked questions
How much folic acid should I take before pregnancy?
US and UK guidance both give 400 micrograms a day for most people: the CDC (2026) and the NHS (2026) give 400 micrograms, and the US Preventive Services Task Force (2023) gives 400 to 800. Higher doses apply to specific groups and are set by a doctor.
When should you start taking folic acid before trying to conceive?
The CDC, the USPSTF and ACOG say at least 1 month before conception. The NHS says ideally 3 months before. All continue it into early pregnancy, through the first 12 weeks in ACOG and NHS guidance.
What is the difference between folic acid and folate?
Folate is the general name for vitamin B9 in all its forms, including those in leafy greens and beans. Folic acid is the form used in supplements and fortified foods, and it is the only form shown to help prevent neural tube defects (CDC, 2026).
Do prenatal vitamins help you get pregnant?
The guidance on this page recommends a prenatal vitamin for the pregnancy, to supply folic acid and iron, not to raise the chance of conceiving (ACOG, reviewed 2025). None of these sources presents a vitamin as a fertility treatment.
Should men take folic acid when trying to conceive?
The folic acid guidance on this page is for the person who could become pregnant. In men, a large trial found that folic acid with zinc did not improve semen quality or live birth rates (Schisterman and colleagues, JAMA, 2020).