Folate for women: why it matters before pregnancy
The difference between folate and folic acid, why folate matters so much before and in early pregnancy, and how much women need.
Reviewed by Emma Carter, Senior Health & Nutrition Editor
Folate is the one supplement with a clear, well-proven case for women who could become pregnant. Getting enough of it before conception and in the first weeks of pregnancy prevents serious birth defects: a Cochrane review of randomized trials found folate supplementation prevents neural tube defects, though without a clear effect on other birth defects (Cochrane review, 2015). Because those weeks often pass before a pregnancy is confirmed, the timing is what makes it matter so much. It is the nutrient every prenatal vitamin is built around.
Folate versus folic acid
The two words get used interchangeably, but they are not quite the same.
| Folate | Folic acid | |
|---|---|---|
| What it is | The natural form of vitamin B9 | The synthetic form |
| Where you get it | Leafy greens, beans, citrus | Supplements and fortified foods |
| Absorption | Less complete from food | More completely absorbed |
| Best for | Everyday intake from a good diet | Preventing birth defects, and topping up |
Both ultimately do the same job in the body: helping make DNA and new cells, and supporting healthy red blood cells.
The pre-pregnancy window
This is the heart of it. In the first few weeks after conception, a structure called the neural tube forms and closes. It becomes the baby's brain and spinal cord. Folate is needed for this to happen properly. If folate is low at that moment, the risk of neural tube defects, such as spina bifida, rises.
The catch is timing. The neural tube closes so early that many women have not yet realized they are pregnant. That is why the advice is to have enough folate on board before conception, not to start once a pregnancy is confirmed.
How much you need
- Most adults: about 400 micrograms of folate a day
- Women who could become pregnant: a 400 microgram folic acid supplement daily, alongside a folate-rich diet
- Higher-risk women: a larger dose, prescribed by a doctor, for example after a previous affected pregnancy, or with diabetes or certain medications
For women planning a pregnancy, starting the supplement a few months beforehand and continuing through the first trimester is the standard recommendation.
Food sources
A folate-rich diet supports your intake even if you also take a supplement. Good sources include:
- Dark green leafy vegetables, especially spinach
- Beans, lentils and other pulses
- Asparagus and brussels sprouts
- Citrus fruit
- Eggs and liver
- Fortified bread and breakfast cereals
Folate from food is part of the broader pattern of micronutrients women benefit from, and it pairs naturally with a diet built on vegetables, pulses and whole grains.
Folate and anemia
Beyond pregnancy, folate matters for making red blood cells. A shortfall can cause a type of anemia that leaves you tired and weak, sometimes alongside low vitamin B12, since the two work closely together. If you have unexplained fatigue, folate and B12 are among the things a doctor may check.
When to see a doctor
See your doctor if you are planning a pregnancy, could become pregnant, or have had a previous pregnancy affected by a neural tube defect, so you get the right folic acid dose for your situation. Also seek advice if you have symptoms of anemia, since low folate is one treatable cause worth confirming with a blood test.
Frequently asked questions
What is the difference between folate and folic acid?
Folate is the natural form of vitamin B9 found in foods like leafy greens, beans and citrus. Folic acid is the synthetic form used in supplements and fortified foods. Folic acid is more completely absorbed, which is why it is the form recommended for preventing birth defects.
Why do women need folate before pregnancy?
Folate is needed to build a baby's neural tube, which forms in the first few weeks of pregnancy, often before a woman knows she is pregnant. Getting enough folic acid before and in early pregnancy reduces the risk of serious birth defects of the brain and spine, such as spina bifida.
How much folic acid should women take?
Adults need about 400 micrograms of folate a day. Women who could become pregnant are advised to take a 400 microgram folic acid supplement daily, on top of a folate-rich diet. Some women at higher risk are prescribed a larger dose by their doctor.
What foods are high in folate?
Dark green leafy vegetables like spinach, along with beans, lentils, asparagus, brussels sprouts, citrus fruit, eggs and liver are all good sources. Many countries also fortify bread and breakfast cereals with folic acid, which adds to your daily intake.
References
- Effects and safety of periconceptional oral folate supplementation for preventing birth defects · Cochrane Database of Systematic Reviews, 2015
- Folate: fact sheet for health professionals · NIH Office of Dietary Supplements
- Folate: fact sheet for consumers · NIH Office of Dietary Supplements