Birth Defect Tests
What does birth defect mean?
A Birth defect means that something has gone wrong with:
- The developing structure of the body parts or their function
- The number and structure of chromosomes or the genes which form part of the chromosomes.
These structural and functional defects lead to physical or mental disabilities in the baby at birth.Babies with major birth defects are in the ratio of two or three out of 100 babies born. Most birth defects occur during the first three months of pregnancy, when the baby’s organs develop. Causes for such birth defects are - they may be inherited through genes or because the mother has had some infection like rubella or chicken pox during pregnancy, or had taken a harmful drug during the early stage of pregnancy. However, causes for defective birth are unknown in about 70 percent of babies.
Common Birth Defects
Common birth defects fall into three categories --- structural, functional and genetic disorders.
Structural defects may be internal like neural tube defects (covering over the spinal cord or brain do not close properly), abdominal wall defects (wall of abdomen is not formed properly and the bowel is seen protruding), heart defect, and abnormalities in the structure of external organs like limbs (a club foot or an extra finger), eyes (crossed eye), ears( Darwinian ear), cleft lip and cleft palate.
Functional defects include malfunctioning of nervous system which lead to mental retardation, speech and learning disabilities and convulsions, sensory defects like blindness, cataracts and other visual problems, and hearing loss, and defects in enzyme functioning.
Genetic disorders occur if a single gene or multiple genes are affected, or if the whole or part of the normal pair of chromosomes is found missing or broken, or there is an additional chromosome instead of the normal pair. Abnormalities in the chromosome result in conditions like Down syndrome, Trisomies 13 and 18, Turner syndrome, and some more similar conditions. If genes are affected, it results in genetic disorders like Thalassemia, Cystic fibrosis, Sickle cell anemia and Haemophilia.
About Tests Performed
Two types of tests are available, first one, known as Screening tests, is to assess if the pregnant mother has any risk of producing a baby with a birth defect and the second one known as Diagnostic tests is offered if you have a greater risk of producing a baby with birth defect, in order to confirm if the baby in the womb actually has a birth defect.
