Birth Defects and the Maternal Diet

Birth Defects and the Maternal Diet

Proper nutrition prior to conception and during pregnancy can help prevent birth defects. Learn about the different nutrients to include in your diet.

Birth defects, which are structural or functional abnormalities present at birth, result in physical and mental disabilities. They are also the leading cause of death in infants less than 1 year of age. With proper maternal nutrition or dietary supplements both prior to and during pregnancy, some of the thousands of types of known birth defects can be prevented.

The Maternal Diet and Birth Defects

A lack of vitamin B9, more commonly known as folate (or its synthetic form, folic acid), in the mother’s diet can lead to neural tube defects in infants, according to Jennifer K. Nelson, MS, RD, director of clinical dietetics and associate professor of nutrition at the Mayo School of Health Sciences in Rochester, Minn. Neural tube defects, such as spina bifida and anencephaly, are developmental problems with the brain and spinal cord, which usually begin during the first trimester of pregnancy. In an infant with spina bifida, the spinal column does not completely close, resulting in nerve damage and paralysis of the legs. With anencephaly, infants usually do not survive because much of the brain fails to develop.

Getting adequate amounts of folic acid both prior to and during pregnancy, especially during the first trimester, prevents most neural tube defects. The Dietary Recommended Intake (DRI) for folic acid is 400 micrograms (mcg) per day, either from a multivitamin or from foods that contain folate, the natural form of folic acid. Foods high in folate include leafy green vegetables, fortified grains and orange juice, dried beans, peas, and fruits.

Another vitamin that is essential in the prevention of neural tube defects is vitamin B12. The DRI for vitamin B12 for women is 2.4 mcg per day and 2.6 mcg per day during pregnancy. Good sources of vitamin B12 are milk products, meats, poultry, and eggs. Just as with folic acid, women need to meet their vitamin B12 needs prior to conception as well as during pregnancy to lower their risk for neural tube defects. Women who are most likely to have low vitamin B12 levels are those who have intestinal disorders that impede absorption of vitamin B12 and those who eat little or no meat, eggs, or dairy products.

Women with poor or restricted diets are also at risk for delivering babies with neural tube defects “The mother’s caloric intake is extremely important because the needs of the baby are so high,” says Nelson.

Other conditions caused by improper diet include:

Congenital heart disease: Pregnant women who have a diet low in riboflavin (vitamin B2) and niacin (vitamin B3) are at risk of having babies with congenital heart disease, especially if they eat diets high in saturated fats. Dairy products (low-fat or fat-free to avoid saturated fat), liver, and green leafy vegetables are good sources of vitamin B2, and vitamin B3 can be found in chicken, fish, liver, nuts, and whole grains.

Gastroschisis: A poor pregnancy diet is a contributing factor for gastroschisis, a birth defect in which the infant’s abdominal wall has a fissure or tear. Women who have a diet low in protein or zinc and who have a low body mass index (BMI) are at risk for having an infant with gastroschisis. Inadequate nutrition and smoking during pregnancy can also cause gastroschisis.

Congenital diaphragmatic hernia (CDH): Women whose diets are low in vitamin B12, vitamin E, calcium, retinol, and selenium are at risk for having a child with congenital diaphragmatic hernia. CDH is characterized by an opening in the infant’s diaphragm resulting in the contents of the abdomen protruding into the thoracic cavity. Taking vitamin supplements greatly reduces this risk.

Cleft palate: A cleft palate is a birth defect in which the roof of the mouth does not completely close during development. Women on a restricted diet or who aren’t getting the proper nutrition have a chance of delivering a child with cleft palate. A lack of folic acid and vitamin A in the mother’s diet are associated with isolated cleft palate (without a cleft lip).

Fetal alcohol syndrome (FAS): Nelson cautions that pregnant women should also avoid alcohol to prevent having a baby with fetal alcohol syndrome (FAS). “Babies born with FAS are smaller, poorly developed, and have lifelong problems,” says Nelson.

Maternal Diet and Birth Defects: How Prenatal Vitamins Benefit Baby

Getting the proper amounts of nutrients is very important for both mother and baby. “Prenatal vitamin supplements can provide the needed amounts,” says Nelson, adding that iron and calcium supplements are especially important for the developing baby. “A poor diet not only increases a mother’s risk for birth defects, but also contributes to premature births, pregnancies that do not go full term, and high-risk pregnancies,” says Nelson.

“Nutrition is very important,” stresses Nelson. Women who are pregnant need to remember they're eating for two, and plan their diet around the health of their baby.