Birth defect is an abnormality present at birth; a congenital defect. Such abnormalities may be inherited from the parents or they may be the result of an illness, a toxic condition of the pregnant mother, or an abnormal condition in the uterus or the birth passage. Sometimes, more than one cause may be responsible for a birth defect.
A difficult birth may also injure a baby, resulting sometimes in a more or less permanent physical or mental handicap. This is called birth injury rather than a birth defect.
Exactly what is a birth defect? Just about all of us are born with minor defects such as asymmetry (for example, one eye higher than the other), birthmarks, or slight oddities of bone structures.
Only about 3 percent of infants are born with a defect that imposes a handicap on them. One of the most publicized—and also one of the rarest—birth defect is Siamese Twins. Others include such varied conditions such as Mongolism, Cleft Palate, Color Blindness, Hemophilia and Congenital Heart Disease.
Some of these show up at birth, but some may not become apparent until later in the child’s life. A large number of defects can be corrected by surgery or other treatment, especially if detected early. This is one good reason why infants and young children should have frequent and thorough medical, dental and eye examinations.
Some of the common causes of birth defects are:
As many as 80 percent of birth defects are attributable to conditions in the mother’s body, or these same conditions working in combination with heredity. Sometimes, but by no means always, the specific cause of birth defect is known.
Exposure to X-rays or other radiation may produce deformity. The taking of certain medicines may also lead to birth defects. A child may be born with a defective heart or nervous system or other abnormalities if the mother catches measles during the first three months of pregnancy.
A gonorrheal infection in the mother’s birth canal may cause blindness in a baby (although this is not strictly speaking a birth defect, since the newborn infant’s eyes are normal at birth and are blinded after birth by infection picked up during delivery)
This can be prevented by the routine precaution of treating the eyes of a newborn baby with a solution of silver nitrate or an antibiotic.
These are those birth defects that are inherited and passed on in the genes, the minute elements that transmit characteristics from generation to generation. Mental deficiency, eye defects and tendencies to develop various types of disease are only a few of the abnormalities that may be inherited.
Most people are aware of some family traits they would rather be without. If these are serious hereditary defects, the possibility must be faced that they may be passed on to future children. The chances that this will happen in any particular case range all the way from certainty to impossibility.
A specialty in medicine called genetic counselling is concerned with predicting quite accurately what the chances are in specific cases, and thus helping people decide whether or not to have children.
If you want a child but fear that you may pass on hereditary defects, talk it over with your doctor. If you live in a large population center, he may be able to refer you to a qualified genetic counselor.
Some birth defects are unavoidable, but others might be prevented by visiting your doctor regularly throughout pregnancy and following his instruction. Pay particular attention to his advice about food, medication and rest.
Report any illness or abnormal symptoms to him as soon as possible. Do not take medicines or have any injections during pregnancy without first getting your doctor’s consent.
Injury suffered by an infant while it is being born. Thanks to the increasingly widespread practice of paying visits to the doctor early in pregnancy, as well as throughout its course, it is possible to anticipate and avoid difficulties in delivery.
Improvements in techniques of handling abnormal deliveries have also helped greatly to minimize birth damage.
Cesarean section is one of the techniques now frequently used when a difficult birth is anticipated. If the mother’s pelvis is too narrow or if she is unwell, the baby may be brought safely into the world by surgical removal from the uterus by way of the abdomen. The same procedure may be used for subsequent babies.
Head injuries are sometimes suffered by infants during prolonged labor or because of difficulties in delivery. Injury of the nerves branching from the spinal cord may cause paralysis of the arms and hands. The brain may also be damaged during birth, resulting in some degree of Mental Retardation.
Another possible result is Cerebral Palsy, a condition in which there is partial paralysis and defective muscular coordination (not all cases of cerebral palsy are caused by birth injuries; however, techniques of helping cerebral palsy children are highly developed, and outlook is improved if treatment is begun early and continued.)
Brain damage may also result from oxygen starvation during birth. The infant receives oxygen from its mother through the Placenta and Umbilical Cord until its own lungs take over after birth. In some instances, the placenta may become detached before the baby is born or the cord may become so twisted while the infant is passing through the birth canal that oxygen is temporarily cut off and areas of the brain suffer damage.
Some especially well-equipped hospitals have electronic equipment by which, in a difficult or premature birth, a continuous check can be made of the baby’s condition, including the concentration of oxygen in its blood. If the equipment signals any dangerous condition not evident to the eye, emergency measures are taken immediately.
At the opposite extreme are cases where the moment of birth has been artificially delayed by attendants until the doctor can arrive the scene. Only recently has it been shown that this procedure is extremely dangerous for the future development of the baby.
Premature infants are especially susceptible to injury because of their delicate condition. Thus, the best policy is for a mother to avoid anything that may bring the pregnancy to an early termination. The pregnant woman should go about her activities in a sensible way; if anything unusual happens, the doctor should be called immediately.
Sources and References
Reader’s Digest Family Health Guide and Medical Encyclopedia
Gene-Environment Interactions: Aligning Birth Defects Research with Complex Etiology by Tyler Beames and Robert Lipinski
Risk Factors for Birth Defects by Benjamin Harris, Katherine Bishop et al
The Global State of the Genetic Counseling Profession by MaryAnn Abacan, Lamia Alsubaie et al