Guide

Supplements in pregnancy and when trying to conceive: the NHS essentials

The NHS advises just two supplements around pregnancy: 400 micrograms of folic acid daily, ideally from before conception to 12 weeks, and 10 micrograms of vitamin D daily through pregnancy and breastfeeding. Avoid supplements containing vitamin A (retinol). A prenatal multivitamin is a convenient way to cover the essentials, but always check the label and discuss your supplements with your midwife or GP.

Folic acid: the one to start before you conceive

Folic acid is the synthetic form of folate, a B vitamin. The NHS advises 400 micrograms a day from before conception until the twelfth week of pregnancy, because it reduces the risk of neural tube defects such as spina bifida, which form in the very early weeks when many women do not yet know they are pregnant. That timing is why the advice is to start when you begin trying, not when you get a positive test.

Some women are advised a higher 5 milligram dose, for example with a higher BMI, diabetes, a previous affected pregnancy or certain medications. That is a prescription decision, so raise it with your GP or midwife if it might apply to you.

Vitamin D: throughout pregnancy and breastfeeding

The NHS advises 10 micrograms (400 IU) of vitamin D a day during pregnancy and while breastfeeding, since vitamin D contributes to the maintenance of normal bones and supports the developing baby's bone health. Unlike folic acid, the advice continues through the whole pregnancy and beyond. Compare products in both micrograms and IU; 10 micrograms equals 400 IU. See our vitamin D guide for how to read a label.

The one to avoid: vitamin A

The NHS advises against supplements containing vitamin A (retinol) in pregnancy, because too much can harm the baby. This is the single most important reason to choose a product designed for pregnancy rather than a general multivitamin, and to read the label rather than assume. High-vitamin-A foods such as liver and pate are also best avoided.

What about iron, omega-3 and the rest?

The NHS does not recommend routine iron supplements in pregnancy; iron is added only if a blood test shows you need it, because too much can cause problems and tiredness has many causes. Address iron through your midwife rather than self-prescribing. Omega-3 (DHA) supports the baby's normal brain and eye development, but it is not on the NHS essentials list and oily fish in the diet is the usual first route. See our iron guide for why a test comes first.

How to read a prenatal label

Compare brands

See our roundup of the best prenatal vitamins in the UK, and the full trying to conceive and pregnancy hubs.

Sources

Frequently asked questions

Which supplements does the NHS advise in pregnancy?

Two. The NHS advises 400 micrograms of folic acid a day, ideally from before conception until you are 12 weeks pregnant, and 10 micrograms of vitamin D a day throughout pregnancy and while breastfeeding. Everything else depends on diet and individual circumstances and is best discussed with your midwife or GP.

Why should I avoid vitamin A in pregnancy?

The NHS advises against supplements containing vitamin A (retinol) in pregnancy because too much can harm the developing baby. This is why a prenatal product is not the same as an ordinary multivitamin, and why you should check the label. Liver and liver products are also high in vitamin A and are best avoided.

Do I need a special prenatal multivitamin?

Not necessarily. The two things that genuinely matter, folic acid and vitamin D, can be bought as single supplements and are available free for many through the NHS Healthy Start scheme. A prenatal multivitamin is a convenient way to cover them, but check it contains the right amounts and no vitamin A, rather than trusting the word "pregnancy" on the box.

Should some women take more folic acid?

Some women are advised a higher daily dose of 5 milligrams of folic acid, for example those with a higher BMI, diabetes, a family history of neural tube defects or taking certain medicines. That higher dose is prescribed by a clinician, so if any of these apply to you, raise it with your GP or midwife rather than self-prescribing.

This is information, not medical advice, and is not a substitute for a registered clinician. Always discuss your supplements with your midwife or GP, and read product labels carefully in pregnancy.

OM

Oliver Mackman

Editor, Her Vitals

Oliver leads Her Vitals's editorial coverage of women's life-stage health and supplements. He curates and reviews existing branded products across trying to conceive, pregnancy, postnatal, perimenopause, menopause and the senior years, weighing what the evidence supports against guidance from bodies such as EFSA, the NHS and NICE, and is clear that the content is information rather than medical advice.

Last reviewed: 12 June 2026