Almost everyone agrees prenatal vitamins are important: 96% of our readers say expecting mums should take them (2,475 votes).
The timing is where it goes wrong, and it goes wrong for about half of everyone.
“When did you start taking folic acid?” 4,123 votes
- 54%: During pregnancy
- 39%: Before pregnancy
- 6%: Before marriage
And asked directly whether they took folic acid before conceiving, 51% of 5,123 readers said no.
Why this matters more than it sounds. Folic acid’s main job is preventing neural tube defects: serious malformations of the brain and spine. The neural tube closes by about day 28 after conception, which is roughly when a missed period is noticed. Starting once you know you’re pregnant is frequently after the window it was protecting.
Nobody should feel guilty about this. Half of all pregnancies are unplanned and the message isn’t well communicated. But it changes the advice: if a pregnancy is anywhere on the horizon, start now.
What you need
| Nutrient | Why | Notes |
|---|---|---|
| Folic acid | Prevents neural tube defects | 400mcg daily, from at least a month before conceiving through the first 12 weeks. Non-negotiable. |
| Iodine | Foetal brain and thyroid development | Commonly under-supplied. Not all salt sold here’s iodised. |
| Iron | Blood volume nearly doubles | Needs rise sharply in the second and third trimesters. Deficiency is very common locally. |
| Vitamin D | Bone development; widespread insufficiency | Yes, even on the equator: indoor life and sun avoidance mean deficiency is common in Singapore. |
| Calcium | Skeletal development | If it doesn’t come from the diet, it comes from your bones. |
| DHA (omega-3) | Brain and eye development | Often a separate capsule. Reasonable to take; not as essential as folic acid. |
The one you must avoid
Don’t take a supplement containing retinol (preformed vitamin A).
High-dose retinol is teratogenic: it can cause birth defects. This is precisely why you take a prenatal multivitamin instead of an ordinary one: many general multivitamins contain retinol at doses that are fine for anyone else and not fine in pregnancy.
Beta-carotene is a different thing and is safe. The label will distinguish them. Also skip liver and liver pâté, which are extremely high in retinol.
Two more:
- Don’t double up. A prenatal plus separate iron plus a “pregnancy booster” can push you past safe upper limits, particularly for vitamin A and iron. One prenatal is the baseline; add anything else only on advice.
- Herbal and traditional supplements are largely untested in pregnancy. “Natural” isn’t a safety claim. Check with your doctor before taking any, including ones a relative recommends warmly.
How to choose one
Prenatal vitamins are a well-marketed category and the marketing is largely noise. Our readers are already sceptical about supplements generally: only 26% think they’re worth the money, and 63% say only some are (838 votes).
- Check it contains 400mcg folic acid, plus iodine, iron and vitamin D. That’s the test.
- A cheap generic meeting those numbers does the same job as an expensive brand meeting the same numbers. There’s no premium version of folate.
- Check the retinol. If it lists vitamin A as retinol or retinyl palmitate at any meaningful dose, put it back.
- Gummies frequently contain no iron: it tastes metallic, so it’s left out. Pleasant to take, incomplete.
- Buy from a pharmacy or reputable retailer. Supplements bought through social media sellers or from overseas marketplaces may not contain what the label says.
- Your polyclinic or obstetrician can prescribe, which removes the guesswork entirely.
When you need more than the standard dose
Some women need 5mg of folic acid instead of 400mcg, more than ten times the usual amount. This must be prescribed, not self-selected. It generally applies if you:
- Have had a previous pregnancy affected by a neural tube defect
- Have diabetes
- Take anti-epileptic medication
- Have a BMI over 30
- Have sickle cell disease or thalassaemia
- Have coeliac disease or another condition affecting absorption
Thalassaemia carrier status is common in Singapore, and it also changes how iron supplementation should be handled. If you know you’re a carrier, say so. Don’t simply take iron because pregnancy usually needs it.
Taking them without feeling sick
- Take them with food, never on an empty stomach.
- At night, if nausea is bad: you sleep through the worst of it.
- Iron causes constipation. Expect it, and increase water and fibre instead of stopping the iron.
- Iron also blackens stools. Normal, and alarming if nobody warns you.
- Vitamin C helps iron absorb; tea and coffee at the same time hinder it. Space them by an hour.
- Keep taking them while breastfeeding. Requirements stay high, and stores are usually depleted by the birth.
- If you can’t keep them down at all because of severe sickness, tell your doctor instead of just stopping.
Frequently asked questions
When should I start taking folic acid?
At least one month before conceiving, and continuing through the first 12 weeks. The neural tube closes by around day 28 after conception, about when a missed period is noticed, so starting once a pregnancy is confirmed is often after the window it protects. Half our readers took none before conceiving, and 54% started only during the pregnancy.
How much folic acid do I need?
400mcg daily for most women. A much higher 5mg dose is used for some: a previous pregnancy affected by a neural tube defect, diabetes, anti-epileptic medication, BMI over 30, sickle cell or thalassaemia, or absorption conditions. That higher dose must be prescribed, not self-selected.
Can I take an ordinary multivitamin instead of a prenatal one?
No. Many general multivitamins contain retinol, the preformed type of vitamin A, which in high doses can cause birth defects. That’s the main reason prenatal formulations exist. Beta-carotene is a different form and is safe. The label distinguishes them.
Are expensive prenatal vitamins better?
Not if the numbers match. Check for 400mcg folic acid plus iodine, iron and vitamin D; a cheap generic meeting those does the same job as a premium brand meeting those. Note that gummies often omit iron because of the taste.
What supplements should I avoid in pregnancy?
Anything containing retinol or retinyl palmitate, and liver or liver pâté. Avoid doubling up: a prenatal plus separate iron plus a “booster” can exceed safe upper limits. Herbal and traditional supplements are largely untested in pregnancy and should be cleared with your doctor first, however warmly they’re recommended.
Do prenatal vitamins make you feel sick?
They can, especially the iron. Take them with food, or at night so you sleep through the worst. Expect constipation and black stools from iron, take vitamin C alongside to help absorption, and keep tea and coffee an hour apart from it. If severe sickness stops you keeping them down, tell your doctor instead of stopping on your own.
Should I keep taking them after birth?
Yes, while breastfeeding. Requirements remain high and stores are usually depleted by the birth.
What to remember
Start folic acid before you conceive: 400mcg, a month ahead. That’s the one thing on this page that has a deadline, and half of readers missed it.
Buy on the label, not the brand: 400mcg folic acid, plus iodine, iron and vitamin D. Check it has no retinol.
Don’t stack supplements on top of it, and clear any herbal remedy with your doctor first.
Read next
- Iron deficiency: why three in four Singapore mums run low
- What a baby costs in Singapore
- Pregnancy anxiety: 55% struggle, 1.5% get help
This article is general information and not a substitute for medical advice. Supplement doses in pregnancy should be confirmed with your doctor, polyclinic or pharmacist, particularly if you have any condition listed above.