About one in every 33 babies is born with a birth defect. Find information on birth defects, including what causes them, how they're diagnosed, and how they can be prevented. A birth defect is a problem that happens while a baby is developing in the mother's body. Learn about the different types of birth defects, their treatments, and how some kinds can be prevented. supporting families who have children with congenital disorders and associated disabilities; and strengthening research on major birth defects and promoting international cooperation in combatting them. Together with partners, WHO convenes annual training programmes on the surveillance and prevention of congenital disorders. Join our National Birth Defect Registry to connect with other families, access trusted resources, and contribute to research that improves care and outcomes for all children. Birth Defects Summary: Key Facts What is a birth defect? A birth defect (congenital disorder or anomaly) is a structural or functional problem present at birth, affecting how the body looks, works, or both. How common are. A birth defect[a] is an abnormal condition that is present at birth, regardless of its cause. [2] Birth defects may result in disabilities that may be physical, intellectual, or developmental. [2] The disabilities can range from mild to severe. [6] Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional. Birth defects can happen for many reasons. They can happen because of the mother’s exposure to certain environmental factors, infections, or illegal drugs. They can also occur if there is a vitamin deficiency during pregnancy. Or they can happen because of certain genes or changes in genes (mutations). It could also be a combination of these. Understand the causes of birth defects, including lifestyle, medications, infections, and environmental exposures. Read for prevention tips. A birth defect, also called a congenital disorder or condition, occurs when a baby develops differently from normal in the womb. In some cases, these differences can cause life-long challenges. There are several types of birth defects, with causes that range from genetic changes to environmental factors. Examples include congenital heart conditions, a cleft lip and Down syndrome. You can’t prevent most birth defects but you can reduce your risk by maintaining good health. Birth defects, now known as congenital anomalies, are conditions that a person has from birth. Examples include cleft lip, Down syndrome, and spina bifida.