What Happens If You Dont Take Folic Acid In Pregnancy?

Folic acid is one of the few nutrients with a clear, proven job in early pregnancy. It helps the neural tube — the structure that becomes the brain and spinal cord — close properly during the first weeks after conception. If you don’t get enough, the risk of a neural tube defect rises. That risk is highest in the first month of pregnancy, often before a woman knows she is pregnant.

This is why public health agencies recommend folic acid for anyone who could become pregnant, not just those who are trying. The key detail is timing. By the time a positive test shows up, the neural tube has usually already closed. So “not taking folic acid” carries different consequences depending on when the gap happens.

What Happens If You Don’t Take Folic Acid In Pregnancy?

The main consequence is a higher chance of a neural tube defect in the baby. The neural tube is the early tissue that folds and closes to form the brain and spinal cord. That closure happens in the first 28 days after conception.

When folate levels are too low during this window, the tube may not close completely. The result depends on where the gap occurs. If the upper end stays open, it causes anencephaly — a condition in which major parts of the brain and skull do not form. Babies with anencephaly do not survive. If the lower end stays open, it causes spina bifida, in which the spinal cord and its coverings are exposed or poorly protected.

These are serious, life-altering conditions. Spina bifida can cause paralysis, bladder and bowel problems, and fluid buildup in the brain. The severity varies widely. Some people with the mildest forms live largely independent lives. Others need lifelong care.

Folic acid does not prevent all neural tube defects. It reduces the risk. Some cases have genetic or other causes that folic acid cannot address.

Why Is the First Month So Important?

Because the neural tube closes before most women know they are pregnant. Conception happens, and within about four weeks the tube has already finished closing. A missed period and a positive test often come after that point.

This timing is the whole reason folic acid advice targets people who might get pregnant, not people who are already pregnant. Waiting until a positive test to start can mean missing the window that matters most.

Roughly half of pregnancies in the United States are unplanned. That number is a big part of why the recommendation is broad. It is not a judgment about planning. It is a practical response to biology.

How Much Folic Acid Do You Need?

For most people who could become pregnant, the standard recommendation is 400 micrograms (mcg) of folic acid per day. This is the amount in most prenatal vitamins and many basic multivitamins. It is also the level added to fortified foods like enriched grains and cereals in the US.

Some people need more. A higher dose — typically 4,000 mcg (4 mg) per day — is often recommended for those with a previous pregnancy affected by a neural tube defect, or those taking certain medications, or with specific conditions like diabetes or obesity. That higher dose should come from a clinician, not a guess.

Two points that get confused:

• Folic acid is the synthetic form used in supplements and fortified foods. It is well absorbed.
• Folate is the natural form found in foods like leafy greens, beans, and citrus. It is also important, but harder to get enough of through diet alone.

Food folate counts, but it is difficult to reach the recommended amount from food alone without deliberate effort. Fortified foods and supplements close the gap. The evidence for folic acid supplements specifically is stronger than for food folate in preventing neural tube defects.

Does Not Taking It Always Cause a Problem?

No. Many pregnancies proceed normally even without folic acid supplements. Neural tube defects are relatively uncommon, and not every low-folate pregnancy results in one.

But “not always” is not the same as “safe to skip.” The supplement reduces risk across a whole population. On an individual level, you cannot predict which pregnancy will be affected. That is the nature of risk reduction — it works statistically, not as a guarantee either way.

It helps to separate two ideas:

• Folic acid lowers the chance of a neural tube defect.
• It does not eliminate the chance, and skipping it does not guarantee a defect.

Both statements are true at once. People sometimes hear one and forget the other.

What About Taking It Later in Pregnancy?

Folic acid still matters after the neural tube closes, but for different reasons. It supports rapid cell division and blood cell production throughout pregnancy. Low levels are linked to maternal anemia. Some research suggests a relationship with preterm birth and other outcomes, though the evidence there is less consistent than for neural tube defects.

The strongest, clearest evidence is for the early window. Later pregnancy needs are real, but the case is not as airtight. This is one reason prenatal vitamins include folic acid throughout — it covers both the well-established early need and the likely later need.

A common misconception is that starting folic acid in the second trimester is pointless. It is not pointless. It is just past the window for the specific protection that gets the most attention.

What Foods Contain Folate?

Folate occurs naturally in several foods. Fortified foods add folic acid, which is absorbed even better. Here is a rough comparison of common sources.

These figures come from USDA nutritional data. They show that food can contribute meaningfully. But hitting 400 mcg every single day from food alone takes planning, and absorption from food varies. This is why supplements remain the standard recommendation for pregnancy.

Are There Any Risks From Taking Folic Acid?

For most people, folic acid at recommended levels is considered safe, and it has been used widely for decades. The main caution is about very high doses over long periods without medical supervision.

Some research has raised questions about whether very high folic acid intake could mask a vitamin B12 deficiency, which matters most in older adults. In pregnancy, the concern is less clear. There is no strong evidence that the standard 400 mcg dose causes harm.

If you are taking a higher dose for a specific reason, that should be guided by a clinician. More is not automatically better, and the appropriate dose depends on your situation.

What Should You Do If You Are Already Pregnant?

Start taking a prenatal vitamin with folic acid now if you are not already. It may still help with later pregnancy needs even if the early neural tube window has passed. Tell your clinician what you are taking and how far along you are.

If you are not pregnant but could become pregnant, this is the time to start. The recommendation is not about being pregnant today. It is about having enough folate on board before the window that matters, because that window opens before most people know it has arrived.

No supplement replaces a conversation with a doctor. If you have a personal or family history of neural tube defects, or take medications that affect folate, that conversation should happen before pregnancy if possible.