Pregnancy Vitamins: What the NHS Recommends and What to Avoid

The NHS asks for two supplements in pregnancy and names one to avoid: folic acid, 400 micrograms a day from before conception to week 12; vitamin D, 10 micrograms a day, at least from early October to late March; and no cod liver oil or vitamin A supplements. Iron is checked by blood test.¹ This page belongs to the Wellgard vitamins and minerals guide.

Evidence at a glance

• Trials: five Cochrane pooled analyses, one iodine review, two randomised trials and two cohorts.
• Largest single trial cited: 1,817 women with a previous affected pregnancy, 33 centres.
• Strongest measured outcome: neural tube defects about two thirds lower with folic acid (5 trials, 6,708 births, high-quality evidence).
• Not tested in a UK trial: iodine supplements in pregnancy and child development.

Sources checked on 13 October 2026.

What vitamins should I take when pregnant, according to the NHS?

Folic acid and vitamin D; iron if a blood test shows you need it; no vitamin A.¹

Who needs the higher 5 mg dose of folic acid?

The NHS recommends 5 mg a day, which a GP can prescribe, when planning a pregnancy and up to 12 weeks if you or the baby's father has a neural tube defect or a relative with one, you have had an affected pregnancy, you have diabetes or a blood condition such as sickle cell anaemia or thalassaemia, or you take medicine for epilepsy or HIV.¹

The NHS says folic acid "reduces the chance of your baby having a neural tube defect".¹ Across 5 trials and 6,708 births, daily folic acid cut neural tube defects by about two thirds (risk ratio 0.31, high-quality evidence).² In the Medical Research Council trial of 1,817 women with a previous affected pregnancy, 6 affected pregnancies followed with folic acid against 21 without (risk ratio 0.28).³ More on folic acid in pregnancy.

How much vitamin D should you take in pregnancy, and when?

10 micrograms (400 IU) a day from early October to late March; all year if you usually cover most of your skin outdoors or spend a lot of time indoors, and consider it all year if you have black or brown skin. The NHS limit: "Do not take more than 100 micrograms of vitamin D a day".¹

On pregnancy outcomes, the 2024 Cochrane update, after trustworthiness checks set aside 20 earlier studies, rated the evidence on pre-eclampsia, gestational diabetes and preterm birth "very uncertain" (8 studies, 2,313 women against placebo or nothing); one study of 1,134 women found vitamin D may reduce severe bleeding after birth (low certainty).⁴ More on vitamin D in pregnancy and breastfeeding.

Which vitamins should you not take while pregnant?

Vitamin A. The NHS says: "Do not take cod liver oil or supplements containing vitamin A", sometimes called retinol, as "Too much vitamin A can harm your baby's development."¹ Liver is on the NHS foods-to-avoid list for its "high levels of vitamin A".⁵

In 2024 the European Food Safety Authority kept 3,000 micrograms a day of preformed vitamin A as the adult upper level, pregnancy included, set on birth defects; a European figure, not UK advice.⁶ In a US cohort of 22,748 pregnant women, more than 10,000 IU (3,000 micrograms) a day from supplements went with 4.8 times the rate of cranial-neural-crest defects seen at 5,000 IU or less, mostly from intake before week 7; the authors estimated that about 1 baby in 57 in that group had a malformation attributable to the supplement.⁷

Is iron checked in pregnancy, and when are supplements given?

Yes: at the booking appointment and at around 28 weeks. If levels are low, "Your GP or midwife will recommend you take iron supplements."¹ Iron contributes to normal formation of red blood cells and haemoglobin; in the 2024 Cochrane review of 57 trials and 48,971 women, daily iron meant less maternal anaemia than placebo or none (4.0% against 7.4%; low certainty) and probably fewer low-birthweight babies (5.2% against 6.1%; moderate certainty).⁸ See foods high in iron.

Do you need iodine in pregnancy?

The NHS pregnancy vitamins page does not mention iodine.¹ The NHS iodine page gives adults 140 micrograms a day, suggests strict vegans consider fortified foods or a supplement after professional advice, and says 0.5 mg or less a day from supplements is unlikely to cause any harm.⁹

In 2019 to 2023, UK women of childbearing age had a median urinary iodine of 82 micrograms per litre, below the survey threshold of 100 for adequate population status.¹⁰ In a UK cohort of 1,040 pregnant women, low iodine in early pregnancy went with more children in the lowest quarter for verbal IQ at 8 (odds ratio 1.58).¹¹ Iodine contributes to the normal production of thyroid hormones and normal thyroid function; in a trial of 832 mildly deficient pregnant women in India and Thailand, 200 micrograms a day did not differ from placebo on child IQ at 5 to 6,¹² and a 2020 review found "insufficient good-quality evidence" for supplementing in mild to moderate deficiency.¹³ Seaweed iodine varies: see what sea moss is and why its iodine varies.

Should you take omega-3 or fish oil in pregnancy?

The NHS pregnancy page lists no omega-3 supplement, and cod liver oil is on its avoid list because of vitamin A.¹ Oily fish is limited to 2 portions a week because of pollutants.⁵ Across 70 trials and 19,927 women, omega-3 from supplements or food cut early preterm birth, before 34 weeks, from 4.6% to 2.7% (9 trials, high-quality evidence), while pregnancies past 42 weeks rose from 1.6% to 2.6% (moderate quality).¹⁴ Fish body oil is not cod liver oil; see what the fish oil research found.

What does the NHS say about multivitamins, choline, B6 and other supplements?

The NHS pregnancy page gives no specific advice on choline, vitamin B6, vitamin C, calcium, magnesium or zinc; it says "If you need higher dose folic acid or other supplements, speak to a GP."¹ Its folic acid page adds: "check with a doctor or pharmacist before taking a multivitamin that contains folic acid".¹⁵

In 20 trials of 141,849 women, 19 in low- and middle-income countries, a multiple-micronutrient supplement with iron and folic acid meant 12% fewer low-birthweight babies than iron with or without folic acid (high-quality evidence), with no difference in newborn deaths; the one UK trial found no important difference from placebo in low birthweight or preterm birth, and less late-pregnancy anaemia.¹⁶ These results are not UK advice. See also collagen in pregnancy, creatine while pregnant or breastfeeding and BV, thrush and UTIs in pregnancy.

How do you check a pregnancy vitamin label?

Check it against the NHS:

• Folic acid: 400 micrograms (also written mcg or µg).
• Vitamin D: 10 micrograms (400 IU); with a separate vitamin D as well, keep the total under 100 micrograms a day.
• Vitamin A (retinol): none, and no cod liver oil; "Always check the label."¹
• Iodine: if listed, the NHS general line is 0.5 mg or less a day.⁹

Many pregnancy multivitamins already contain vitamin D, so check before adding a second product; how to choose a multivitamin for women covers the rest.

Can you get free pregnancy vitamins?

Yes, if you are on the NHS Healthy Start scheme. Its tablets contain folic acid, vitamin C and vitamin D and cover pregnancy until your baby's first birthday; its drops for children under 4 contain vitamins A, C and D. In England and Wales: "Ask your midwife or health visitor where to get your free vitamins."¹⁷

What we don't know

• Whether iodine supplements change child development for UK women: the trial ran in India and Thailand.
• Whether a pregnancy multivitamin adds to folic acid and vitamin D for UK women: the one UK trial measured few outcomes.
• What the vitamin D evidence shows once 34 studies awaiting assessment are classified.
• Whether supplemental vitamin A below about 10,000 IU a day carries risk: the cohort found an apparent threshold, not a tested safe level.

Frequently asked questions

Do I need prenatal vitamins in the UK?

The NHS asks for folic acid and vitamin D, not a particular product.¹ A pregnancy multivitamin takes both in one tablet; separate supplements or Healthy Start tablets are other routes.

When can I stop taking folic acid?

After the first 12 weeks, says the NHS, adding: "If you take it for longer than this, it will not harm your baby."¹ On the 5 mg dose, ask your GP.

Is it too late to start folic acid at 7 weeks?

No. The NHS says to start "as soon as you find out you're pregnant" and continue to week 12.¹

Sources

1. NHS. Pregnancy vitamins and supplements. Page last reviewed 3 June 2026. nhs.uk/pregnancy/keeping-well/pregnancy-vitamins-and-supplements
2. De-Regil LM et al. Cochrane Review 2015. Pooled analysis of 5 trials, 7,391 women. PubMed 26662928
3. MRC Vitamin Study Research Group. Lancet 1991. Randomised trial, 1,817 women. PubMed 1677062
4. Palacios C et al. Cochrane Review 2024. Pooled analysis of 10 studies; 8 studies, 2,313 women against placebo or none. PubMed 39077939
5. NHS. Foods to avoid in pregnancy. Page last reviewed 15 June 2026. nhs.uk/pregnancy/keeping-well/foods-to-avoid
6. EFSA Panel on Nutrition. EFSA Journal 2024. Scientific opinion from systematic reviews: upper intake level for preformed vitamin A. doi.org/10.2903/j.efsa.2024.8814
7. Rothman KJ et al. N Engl J Med 1995. Observational cohort, 22,748 pregnant women. PubMed 7477116
8. Finkelstein JL et al. Cochrane Review 2024. Pooled analysis of 57 trials, 48,971 women. PubMed 39145520
9. NHS. Iodine. Page last reviewed 3 August 2020 (review overdue). nhs.uk/conditions/vitamins-and-minerals/iodine
10. OHID. National Diet and Nutrition Survey 2019 to 2023. National survey, urine samples from 344 women aged 16 to 49, published 11 June 2025. gov.uk
11. Bath SC et al. Lancet 2013. Observational cohort, 1,040 pregnant women. PubMed 23706508
12. Gowachirapant S et al. Lancet Diabetes Endocrinol 2017. Randomised trial, 832 pregnant women, children followed to 5 to 6. PubMed 29030199
13. Dineva M et al. Am J Clin Nutr 2020. Systematic review, 37 studies including 10 randomised trials. PubMed 32320029
14. Middleton P et al. Cochrane Review 2018. Pooled analysis of 70 trials, 19,927 women. PubMed 30480773
15. NHS. Folic acid (medicines). Page last reviewed 5 May 2026. nhs.uk/medicines/folic-acid
16. Keats EC et al. Cochrane Review 2019. Pooled analysis of 20 trials, 141,849 women. PubMed 30873598
17. NHS Healthy Start. Getting vitamins. No review date; checked 13 October 2026. healthystart.nhs.uk/getting-vitamins

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