Is Excess Folic Acid During Pregnancy Harmful For The Baby?

A healthy pregnancy is often kick-started with a good dose of folic acid. Most physicians advise this step as soon as you plan a baby. Responsible for cell growth and development, folic acid in adequate amounts in your diet can protect your baby from defects of the brain or spinal cord. It is also essential for its brain development and function.1 But like any other nutrient component, there are chances of over-supplementation. Excessive amounts of folic acid can pose various health risks for the mother and the developing baby.

Autism Spectrum Disorder

Recent research shows that too much folic acid may result in nervous tissue damage associated with autism. In one study, researchers analyzed data from 1391 mother–child pairs at the Boston Birth Cohort. Over-supplementation and high maternal levels of folic acid were found to increase the baby’s risks of developing autism spectrum disorder, a neurodevelopmental condition that affects social interaction, abnormal communication, and unusual behavior.2


Cancer Risk

Animal studies have shown that a high dietary intake of folic acid may increase the risk of mammary tumors. Higher levels of folic acid have also been associated with increased maternal cancer risk.3 The role of folic acid in the risk of colorectal cancer and some other cancers is also under the scanner. However, these studies are at a preliminary stage, and more evidence-based studies are required to establish the connection.4

Cognitive Decline

High folic acid intake can also mean a faster rate of cognitive decline. Studies point out that folic acid in supplements and fortified foods could worsen vitamin B12 deficiency, which has been linked to cognitive decline in older adults.5


Other Health Risks

Excess folic acid supplementation in pregnant women can lead to an increased risk of insulin resistance and obesity in the children.6

Taking large amounts of folic acid might also camouflage a vitamin B12 deficiency. Some studies, however, point out that excessive folic acid can actually worsen the anemia and symptoms associated with B12 deficiency. In either case, the folic acid–B12 equation needs further investigation. If undetected, B12 deficiency can mean permanent damage to the brain, spinal cord, and nerves.7


Naturally occurring folic acid is present in a wide variety of foods such as dark green leafy vegetables, fruits, nuts, beans, peas, dairy products, seafood, and grains. Apart from this, folic acid is also available in multivitamins or as a stand-alone supplement. The US Department of Health and Human Services recommends that pregnant women should take 400–800 micrograms (mcg) of folic acid daily.8

So where does the danger lie for a mom-to-be? Folic acid present naturally in food is not harmful, so you don’t have to be queasy about how much greens or other natural folate-rich foods you eat. Supplements are another matter. Intake of folic acid through supplements and fortified foods should not go beyond the recommended upper limit unless specifically advised by a healthcare provider. More research is needed to determine the right dose of supplementation that will provide optimal levels of this important nutrient without any of the fallout. But till then, play safe and keep tabs on your intake of folic acid supplements.