What causes birth defects?
Genetics In ancient times, abnormalities were seen as warnings or punishments from the gods. Even quite recently, it was believed that specific events during the pregnancy – such as being frightened by a mouse – would lead to specific defects in the baby, eg a mouse shaped birth mark. Such folk beliefs still persist in places. However, most defects that can be traced to a single cause have a genetic origin. This does not necessarily mean that the parents suffer from the same defect. It may be that they are carriers of the condition, or that the genetic problem occurred for the first time in the cells that gave rise to the baby. Known genetic causes account for about 25 per cent of all abnormalities. Environment Environmental causes (including exposure to drugs, radiation and illnesses) can be identified in about 10 per cent of birth defects. The risk of exposure to such environmental factors often causes great concern, although genetic causes are more common. Other factors The exact ca
We know the causes for some birth defects, but the causes of most birth defects are unknown. We do know that genetics, environmental factors, and nutritional, infectious, and other health-related factors during pregnancy play a role, but how big or small a role each plays in causing birth defects overall is the matter of intense research and debate. A growing number of experts believe that most birth defects result from multiple factors. By this interpretation, inherited genes may predispose someone to a birth defect, but one or more environmental factors also must be present to result in a birth defect. This is called a gene-environment interaction. For example, women with a certain form of a gene that is involved in the development of the mouth are more susceptible to having a child with cleft lip or cleft palate, if they also smoke. If they don’t smoke, their risk is much lower. And the risk is also much lower for women who smoke but who don’t have that particular gene. Genetics :we
Birth defects have a variety of causes, such as: Genetic problems caused when one or more genes doesn’t work properly or part of a gene is missing Problems with chromosomes, such as having an extra chromosome or missing part of a chromosome Environmental factors that a woman is exposed to during pregnancy, such as rubella or German measles while pregnant, or using drugs or alcohol during pregnancy. What are the different types of birth defects? There are two main types of birth defects: structural and functional/developmental. Structural birth defects are related to a problem with body parts. Some physical problems include cleft lip or cleft palate, heart defects, such as missing or misshaped valves, and abnormal limbs, such as a club foot. They also include neural tube defects, such as spina bifida, problems that are related to the growth and development of the brain and spinal cord. Functional birth defects are related to a problem with how a body part or body system works. These pro
