Pregnancy & Fertility

Prenatal Vitamins: What to Take & When to Start

Not all prenatal vitamins are equal. Here's what the research actually says you need — and what's just marketing.

Prenatal vitamins supplement the nutrients that pregnancy demands in higher quantities than diet alone typically provides. They're not a replacement for a healthy diet but are an important insurance policy — especially during the first trimester when the neural tube, heart, and brain are forming rapidly, often before you even know you're pregnant.

Start before you conceive: The neural tube closes just 28 days after fertilisation — before most women have a missed period. Folic acid needs to be in your system before conception, not just after a positive test. Start 3 months before you plan to try.

When to Start Prenatal Vitamins

Ideal: 3 months before TTC

Gives folic acid, iodine, and vitamin D time to reach optimal levels in your body.

Good: Start of TTC

Begin as soon as you decide to try for a baby. Better late than never.

Minimum: Start now

If you're already pregnant and haven't started, begin today. Every week counts.

Key Nutrients to Look For

Folic Acid / Methylfolate

Reduces risk of neural tube defects (spina bifida, anencephaly) by up to 70%. Most critical in weeks 3–4 of pregnancy. If you have the MTHFR gene variant, choose methylfolate (5-MTHF) — the active form your body can use directly.

400–800 mcg

Iron

Blood volume increases by 50% during pregnancy. Iron supports red blood cell production and prevents anaemia. Take with vitamin C to boost absorption; avoid taking with calcium or dairy which inhibit it.

27 mg

DHA (Omega-3)

Critical for fetal brain and eye development, especially in the third trimester. Many basic prenatal vitamins don't include it — check your label or take a separate algae-based DHA supplement. Algae-based DHA is suitable for vegans and vegetarians.

200–300 mg

Iodine

Essential for fetal thyroid and brain development. Many prenatal vitamins still don't include adequate iodine. Dairy and seafood are food sources, but many women don't get enough. Often overlooked.

150–220 mcg

Vitamin D3

Deficiency is extremely common and linked to increased risks of preeclampsia, preterm birth, and gestational diabetes. Most prenatal vitamins don't include enough — consider a separate vitamin D3 supplement (1000–2000 IU) if levels are low.

600–2000 IU

Vitamin B12

Works with folate for neural tube development. Critical for vegans and vegetarians who are at higher risk of deficiency. Choose methylcobalamin over cyanocobalamin if possible.

2.6–10 mcg

Choline

Often missing from prenatal vitamins but crucial for brain development. 90% of pregnant women don't get enough from diet alone. Eggs are the richest food source. Look for at least 150–200mg in your prenatal.

150–450 mg

What to Avoid in Prenatal Vitamins

Prenatal Vitamins & Morning Sickness

Iron in prenatal vitamins can worsen nausea, which is already often severe in the first trimester. Strategies that help:

Continue During Breastfeeding

Nutritional demands remain high after birth, especially if you're breastfeeding. Breast milk draws nutrients from your own body, which can deplete your stores. Continue taking a prenatal or postnatal supplement throughout your entire breastfeeding journey — ideally one with added DHA for brain-healthy breast milk.

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Frequently Asked Questions

When should I start taking prenatal vitamins?

Ideally, start taking prenatal vitamins at least 3 months before trying to conceive. Folic acid is most critical in the first 4 weeks of pregnancy — before many women know they're pregnant. If your pregnancy was unplanned, start as soon as you find out.

What nutrients should a prenatal vitamin contain?

A good prenatal vitamin should contain: folic acid (400–800mcg), iron (27mg), iodine (150mcg), vitamin D3 (600–2000 IU), calcium (200–300mg), DHA omega-3 (200–300mg), and vitamin B12 (2.6mcg). Look for methylfolate if you have the MTHFR gene variant.

Can I take a regular multivitamin instead of a prenatal?

Not ideally. Prenatal vitamins contain higher amounts of folate and iron specifically for pregnancy. Regular multivitamins often contain vitamin A (retinol) at levels that can be harmful in pregnancy.

Should I take prenatal vitamins while breastfeeding?

Yes. Nutrient demands remain high while breastfeeding. Continue taking prenatal vitamins throughout breastfeeding, or switch to a postnatal supplement specifically designed for lactation.

Related: How to Get Pregnant Fast · Fertility Diet · Early Pregnancy Symptoms · Ovulation Calculator