Q&A: Preventing Birth Defects

Q: How do I prevent birth defects in my baby?

A: A birth defect is an abnormality of structure, function or body metabolism (inborn error of body chemistry) presenting at birth or early childhood that results in physical or mental disability, or is fatal.  About 120,000 babies (1 in 33) in the United States are born each year with birth defects. Severe birth defects often require lifelong medical treatment and can be a major cause of childhood and adult disability. Birth defects are also the leading cause of infant mortality.

Genetic and environmental factors, or a combination of these factors, can cause birth defects. However, the causes of about 70 percent of birth defects are unknown Birth defects generally are grouped into three major categories: structural/metabolic, congenital infections, and other conditions. Heart defects are the most common type of structural birth defects, affecting one baby in 125. Spina bifida/Neural tube defects affects one in 2,000 babies.( studies have shown that taking folic acid has reduced the incidence of this disease by 19%)   Metabolic disorders are not visible, but can be damaging or even cause death, and affect one in 3,500 babies. PKU (phenylketonuria) is an example of a metabolic disorder in which a build up of a protein in the blood results in brain damage. Fortunately, this disorder can be routinely detected with newborn screening tests, so affected babies can be placed on a special diet that prevents mental retardation.

Rubella (German measles) is probably the best known congenital infection that can cause birth defects. If a pregnant woman is infected in the first trimester, her baby has a one-in-four chance of being born with one or more symptoms of congenital rubella syndrome (deafness, mental retardation, heart defects, blindness). Fortunately, because of aggressive immunization programs, this syndrome has nearly been eradicated in the United States.  Sexually transmitted infections in the mother can also endanger the fetus and newborn. For example, untreated syphilis can cause stillbirth, newborn death or bone defects. About 350 babies were affected by congenital syphilis in the United States in 2006

Other causes of birth defects include (1) Poorly controlled diabetes during pregnancy and (2) substance abuse during pregnancy. Women who are diabetic and whose glucose levels are out of control before pregnancy are at increased risk for a rare but significant defect called caudal regression syndrome.  In this syndrome, infants are born with absence of the tail bone, as well as the pelvis and some vertebrae – resulting in incontinence and major malformations often leading to death. Substance abuse in pregnancy is also a cause of birth defects.  For example, fetal alcohol syndrome (FAS), which affects one baby in 1,000 (about 4,000 babies per year in the United States) and results in mental and physical birth defects, is common in babies whose mothers are heavy drinkers of alcohol during pregnancy. FAS is the most common preventable birth defect in the United States. Babies of mothers who use cocaine early in pregnancy are also at increased risk of birth defects.

What can you do to prevent a congenital defect?
Sometimes the defects may be inherited and you would not know in advance unless there is a history of abnormal children in your family.  If you have such a family history or if you have already had a child with a birth defect you should visit a Geneticist to see exactly what risk you may run of having similar children  born to you and whether the abnormality can be determined by genetic testing via amniocentesis or chorionic villus testing while you are pregnant.  However in most cases following a few basic recommendations will serve you well:

1.  Eat fruits and vegetables and take folic acid 400 mcg daily BEFORE becoming pregnant

2.  Women who have diabetes should get their disease under control before becoming pregnant and then while pregnant continue with the proper diet and meds to stay in control.

3.  Do not drink any alcohol before or during pregnancy.

4.  Do not smoke cigarettes are anything else during pregnancy.

5.  Get early and comprehensive prenatal care. There are routine test your obstetrician will do for you to detect problems early.

6.  Do not take any medications during pregnancy without first discussing them with your Obstetrician.

7.  After the infant is born, allow the infant to have newborn metabolic screening studies done.  These studies are done routinely in all 50 states and U.S. Territories unless parents refuse them. They are done on a blood sample taken from the infant’s heel. These tests detect metabolic disorders that can cause severe mental retardation and/or death early allowing them to be diagnosed and often treated.