Birth Defects Prevention

Birth defects affect about 120,000 babies born in the United States each year. Birth defects account for more than 20% of infant deaths and contribute substantially to life-long disabilities. The causes of about 70% of all birth defects are unknown. Various occupational hazards, dietary factors, medications, personal habits, and environmental exposures may contribute to birth defects, but many questions remain about the exact nature of their influence.

Neural tube defects (NTDs) are one of the most common birth defects. NTDs result when the neural tube (which includes the spinal cord and brain) fails to close during the first month of embryonic development. NTDs include several disorders ranging from spina bifida (incomplete closure of the bones around the spinal cord that can lead to paralysis) to a lack of a cranium (the bones of the head) and its contents, called anencephaly. Approximately 4,000 pregnancies in the United States are affected by NTDs each year.

Key nutritional supplements

• Folic acid: Several studies and clinical trials have shown that 50% or more of NTDs can be prevented if women consume a folic acid-containing supplement (400 mcg per day) before and during the early weeks of pregnancy. For women who have had a previous NTD-affected pregnancy, the Centers for Disease Control and Prevention recommends supplementation with 4,000 mcg per day of folic acid.

Other nutritional supplements that may be helpful

• Multivitamin: Use of a multivitamin supplement during the periconceptional period (defined as the three months prior to pregnancy to the third month of pregnancy) can contribute significantly to a healthy pregnancy.

• Zinc: In a preliminary study, women with the highest total dietary zinc intake before pregnancy (including zinc from both food and supplements) had a 35% decrease in the risk of having an NTD-affected pregnancy. Zinc supplementation (15 mg per day) is considered safe for pregnant women.

Dietary changes that may be helpful

• Caffeine: Non-smoking women who consumed 500 mg of caffeine per day, or roughly five cups of coffee, were twice as likely to suffer a miscarriage compared with women who drank less than one cup of coffee per day. An increased risk of miscarriage was also found in women consuming as little of 100 mg of caffeine per day. This finding appears to indicate that there may be no “safe” amount of regular caffeine consumption during pregnancy. One cup of coffee contains roughly 100 mg of caffeine, depending on how it is brewed (drip coffee contains the most caffeine and instant coffee the least). Black tea contains about 40–70 mg per cup, and a 12-oz. can of caffeinated soda may contain 30–55 mg of caffeine. Caffeine is also found in cocoa, chocolate, and certain over-the-counter medications.