The most common birth defects vary, depending on several factors including where a baby is born and its genetic descent. Some extremely common birth defects include congenital anomalies of the heart, cleft lip and palate, neural tube defects, and gastrointestinal defects. It is important for people to be aware that while some steps can be taken to reduce the risk of birth defects, such as taking vitamins in pregnancy, not all defects are preventable. Prenatal care can help parents identify, address, and prepare for abnormalities of development before the baby is born.
When looking at statistics regarding birth defects, there are a number of factors to consider. Some populations are at higher risk for congenital anomalies that occur as a result of problems with fetal development because of environmental exposure to toxins, poverty that limits access to prenatal care, and their environment. Genetics can also play a role; people of Jewish descent, for example, are more prone to certain genetic conditions. Worldwide, frequency of birth defects is highly variable and different countries experience different rates.
In the United States, the Centers for Disease Control and Prevention have identified heart defects as the most common form of birth defect, occurring in around 1% of babies. Neural tube defects involving the spine and brain are seen in .1% of the population, while cleft lip and palate occur in one in 700-1,000 babies. Other common birth defects include musculoskeletal disorders, metabolic conditions, abnormalities of the eye, and defects in the digestive tract. These birth defects are primarily the result of developmental anomalies.
Genetic disorders occur at varying rates in the population. Some are extremely rare, with only a few documented cases in the entire population. Others, such as chromosomal abnormalities, are relatively common and can be seen in a higher percentage of the population. Genetic disorders are influenced by the age of the mother, as well as the parental genetic history. Screening for defects, including genetic disorders, includes prenatal ultrasound and testing such as chorionic villus sampling.
Another thing to be aware of when examining statistics about birth defects is that anomalies present at birth can be of varying severity in different people. Some heart abnormalities, for example, are fatal, while others are so mild that they may not be discovered until several years have passed. This variance in severity can also lead to variance in statistics because researchers may use different cutoff points when compiling statistics.