Marcia Leighton, age 17, of Gorham, Me., for her question:
ARE THERE MANY KINDS OF BIRTH DEFECTS?
Birth defect rates vary throughout the world. In the United States, it is estimated that about 7 percent of the newborn babies have at least one minor or major defect. A minor defect could be a tiny birthmark which would take no special medical care. A major defect could be a clubfoot which would require medical attention and perhaps surgery.
A birth defect is an abnormal condition a baby has at birth. It is sometimes called a congenital defect. The problem could be in the structure or function of some part of the body, or it may simply be a tendency to develop a certain kind of disease.
There are over a thousand different kinds of birth defects. Scientists are also discovering new ones every year.
Spinal deformity, called spina bifida, or clubfoot can be spotted at birth, but other types of defects are not so obvious. One birth defect, for example, is called Huntington's chorea. Present at birth, it doesn't become apparent until adulthood when the first symptoms are speech and movement problems.
No one knows what causes most birth defects. Factors relating to the baby's heredity and environment may work together to produce many of the abnormalities. Some, however, have a specific environmental or inherited cause. Birth damage is not considered to be a birth defect.
If a mother has German measles during her pregnancy, it is possible that severe harm could come to the baby. Some drugs, X rays and even smoking have been known to cause some damage.
Inherited birth defects can include hemophilia, the disease in which the blood does not clot properly. When a hereditary inability to produce certain enzymes is found, the new baby could be born with such diseases as galactosemia or phenylketonuria.
Certain groups of people can inherit some diseases. Sickle cell anemia, for example, is a blood disease that is found mainly among blacks. Some Jews with ancestors from Eastern Europe could inherit Tay Sachs disease, abnormal deposits of fat in the brain.
Vaccinations of women before pregnancy help to avoid some birth defects. Good general health and medical care throughout the period of pregnancy can also prevent other defects.
Specialists can give medical tests to couples who fear they might be passing on hereditary defects to their babies. Often they can predict the chances of having normal or abnormal children.
Doctors also help most children with birth defects. Some defective children are given assistance by special teachers and therapists.