The correct answer is A. Folic acid is the synthetic form of folate. Folate is a B vitamin that is found naturally in leafy vegetables, citrus fruits, beans, and whole grains. Neural tube defects (NTD), including spina bifida and anencephaly, are the most common disabling birth defects. A substantial amount of evidence has accumulated demonstrating that folic acid deficiency is an important cause of many NTDs and that supplementation with folic acid before conception and during the first trimester can substantially reduce rates of NTDs in the population. Most NTDs develop very early in pregnancy (from 18-30 days after conception) and most women do not present for prenatal care until after 6 weeks' gestation. To prevent NTDs, it is therefore essential that supplementation begin preconceptionally. Current recommendations are that women in the childbearing age group should take a daily vitamin supplement containing 0.4 mg of folic acid.
For women who have previously had an NTD-affected pregnancy or who are on anti-seizure medications, the current recommendations are that the patient takes folic acid 4.0 mg/day (choice B) beginning at least 1 month before conception and continuing through the first trimester. This patient has not had an NTD-affected pregnancy.
To instruct this patient that no supplementation is needed at this time (choice C) would be incorrect. As described, it is essential that women of childbearing age, and especially those trying to conceive, should take 0.4 mg/day of folic acid or 4.0 mg/day if they have had a previous NTD-affected pregnancy.
Vitamin A is a fat-soluble vitamin that is found in milk, cheese, cream, liver, kidney, cod, and halibut fish oil. Although it is an important vitamin for all human beings, it has been shown to be teratogenic when high doses are taken during pregnancy. Several studies have found a link between the intake of greater than 10,000 IU/day of vitamin A during pregnancy and birth defects. This patient therefore should not be advised to take vitamin A 25,000 IU/day (choice D) or vitamin A 250,000 IU/day (choice E) .
PEARL: Folate must be supplemented prior to conception and at least through the first 4 weeks of fetal development to be effective in preventing neural tube defects (NTDs). The dose is 0.4 mg/day in low-risk patients and 4 mg/day in high-risk patients who have a history of an NTD-affected pregnancy. Folate deficiencies may occur as a result of using oral contraceptives, methotrexate, having celiac sprue, or having chronic poor oral intake, which is commonly seen in chronic alcoholics who tend to get all of their calories from alcohol and not green leafy vegetables.
