Birth Defects

Each year, one out of every 28 babies (150,000) is born with a birth defect. There are currently over 4,000 known birth defects. Unfortunately, the causes of about 60% of birth defects are unknown. The rest result from genetic and environmental factors.

A child receives half of its genes from each parent. Since it only takes a single abnormal gene to cause a birth defect, a developing fetus has 100,000 chances to inherit one. Birth defects can also result from environmental factors, such as drug or alcohol abuse, infections, exposure to medication or other chemicals.

There are three major categories of birth defects: structural/metabolic, congenital infections, and other conditions. With structural birth defects, some part of the body (internal or external) is missing or malformed. Metabolic disorders are generally recessive genetic diseases that result from the inability of cells to produce an enzyme needed to change certain chemicals into others or to carry substances from one place to another. Congenital infections occur when an infected mother passes the infection onto her baby (ex. Rubella).

Other causes include fetal alcohol syndrome, which affects about one baby in every 1,000; Rh disease of the newborn, which is caused by the incompatibility between the blood of the mother and her fetus, and affects about 4,000 infants a year. Also, babies of mothers who use cocaine early in pregnancy are at an increased risk of being born with birth defects.

Birth defects are not completely preventable, but there are steps that a woman can take to reduce her risk. The most important step is to set up a pre-pregnancy visit with her health care provider. This step is crucial for women with existing medical conditions, such as diabetes, epilepsy, and high blood pressure. It is also a good idea to start taking a multi-vitamin, avoiding alcohol, smoking, and street drugs.

There is a possibility that some birth defects can be diagnosed prior to birth, using one or more prenatal tests. It is also now possible to treat some birth defects before birth, due to advances in prenatal therapy.