Birth Defects

It could be the most frightening news a parent receives, yet it happens every day. The parents of one out of every 28 babies learn that their baby has a birth defect. Birth defects, according to the March of Dimes (MOD), affect 150,000 babies each year. While birth defects range from mild to severe, MOD says they are the leading cause of death in the first year of life. A birth defect, according to the Centers for Disease Control and Prevention (CDC), can affect how a person looks and/or functions. Most defects develop long before the baby is born. According to the CDC, many birth defects happen during the first 3 months of pregnancy. (Read about "Stages of Pregnancy") They can be discovered before birth, at birth, or after birth. The CDC says most are found during a baby's first 12 months of life.

Birth defects are grouped into different categories:

• Structural abnormalities - When any part of the body is either missing or malformed, the defect is described as structural. According to MOD, heart defects and genitourinary defects top the list as the most common structural defects. (Read about "Congenital Heart Defects" "Genitourinary Birth Defects") Spina bifida - a neural tube defect in which there is an open spine and usually a malformation of the spinal cord - is another example of a structural abnormality. (Read about "Neural Tube Defects")
• Chromosome abnormalities - Abnormalities in the number or structure of chromosomes can cause numerous birth defects. Down syndrome, in which a baby is born with an extra chromosome 21, is one of the most common chromosomal abnormalities. (Read about "Genetics" "Down Syndrome")
• Metabolic disorders - Metabolic disorders are not as visible as structural defects, yet they can be extremely severe and sometimes even result in death. MOD says one in 3,500 infants suffer from metabolic disorders. Many of these diseases like Tay-Sachs (Read about "Tay-Sachs") and Phenylkeonuria (PKU) are genetic. They result from the inability of cells to produce an enzyme that is necessary to either change certain chemicals into others, or to move substances from one place to another. PKU and other metabolism disorders can be detected during newborn screenings. (Read about "Newborn Screenings")

The American College of Obstetricians and Gynecologists (ACOG) says that multiple birth pregnancies and pregnancies in older women can carry greater risks of some birth defects. (Read about "Multiple Birth Pregnancies" "Later Age Pregnancy") According to MOD, the causes of about 60 to 70 percent of birth defects are not known. When birth defects can be traced to a cause, possibilities include genetics and environment. For example, ACOG says a baby can be born with a birth defect because the mother was exposed to an infection. (Read about "Microorganisms") MOD lists rubella or "German measles" (Read about "Childhood Illnesses") as possibly the best known congenital infection. Another infection - Cytomegalovirus (CMV) - is considered the most common congenital viral infection, according to MOD. It affects about 40,000 babies a year. CMV is a member of the herpes virus family. (Read about "Herpes") Sexually transmitted diseases (Read about "STD's") can also endanger the fetus. MOD says untreated syphilis, for example, can result in stillbirth, newborn death or bone defects. (Read about "Skeletal System") An incompatibility between the blood of a mother and her fetus leads to a birth defect called Rh disease (Read about "Rh Disease"), according to MOD. Other causes of birth defects include fetal alcohol syndrome, which is common among babies whose mothers drink too much during pregnancy. (Read about "Alcoholism") Cocaine use may also increase the risk of birth defects.