Supplement Safety
in Pregnancy

400–800 mcg/day

Essential for neural tube closure (closes by day 28). Continue throughout pregnancy — increases to 5 mg/day if MTHFR positive or previous NTD.

1,000–2,000 IU/day (maintain 100–150 nmol/L)

Critical for fetal bone development, immune programming, and placental function. Safe throughout pregnancy.

DHA 200–300 mg/day minimum

DHA is essential for fetal brain and retinal development. Safe throughout pregnancy. Prioritise DHA over EPA in pregnancy.

As directed

Switch to a pregnancy-specific prenatal that contains methylfolate, not folic acid. Provides iodine, iron, B12, and zinc.

200–300 mg/day

Safe in pregnancy. May reduce leg cramps and improve sleep. Avoid magnesium oxide — poor absorption and laxative effect.

As directed

Safe throughout pregnancy. Reduces risk of gestational diabetes, Group B Strep colonisation, and preterm birth in some studies.

Reduce to 100–200 mg/day or stop

Evidence for safety in early pregnancy is limited. Most practitioners recommend reducing dose or stopping at positive pregnancy test. Discuss with your practitioner.

Reduce or stop at positive test

Limited safety data in human pregnancy. Animal studies show no harm but human RCT data is insufficient. Discuss with practitioner.

Stop immediately at positive test

Berberine crosses the placenta and has been associated with neonatal jaundice and potential harm to fetal development. Stop immediately on positive pregnancy test.

Discuss with practitioner

Some evidence for safety in PCOS pregnancy (reduces GDM risk). However, high-dose supplementation in early pregnancy requires practitioner guidance.

Stop — use beta-carotene instead

Preformed vitamin A (retinol) >10,000 IU/day is teratogenic. Avoid cod liver oil and high-dose retinol supplements. Beta-carotene (provitamin A) is safe.

Stop all herbal supplements

Most herbal supplements lack pregnancy safety data. Several are contraindicated (black cohosh, dong quai, pennyroyal, blue cohosh). Stop all herbal supplements at positive test unless specifically advised by practitioner.

Discuss with practitioner

Melatonin is produced endogenously and plays a role in placental function. Low-dose (0.5–1 mg) may be safe but high-dose supplementation in pregnancy lacks sufficient safety data.

Only if deficient — check ferritin

Iron requirements increase significantly in pregnancy. Supplement only if ferritin <30 mcg/L — excess iron increases oxidative stress. Prenatal multivitamin usually provides sufficient iron.