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