Birth defect

A birth defect is an abnormal condition that is present at birth, regardless of its cause. These conditions can lead to disabilities that are physical, intellectual, or developmental, ranging from mild to severe. Birth defects are of two main types: structural disorders, where there are problems with the shape of a body part, and functional disorders, where issues affect how a body part works. Functional disorders can include metabolic and degenerative problems. Some birth defects involve both structural and functional issues.

Birth defects may come from genetic or chromosomal disorders, exposure to certain medications or chemicals, or infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and maternal age over 35 years. Many birth defects likely result from a mix of several factors. Some defects can be seen at birth, while others are found through screening tests or prenatal tests.

Treatment for birth defects depends on the specific condition and can include therapy, medication, surgery, or assistive technology. As of 2015, birth defects affected about 96 million people worldwide. In the United States, they occur in about 3% of newborns. Some of the most serious birth defects leading to deaths include congenital heart disease and neural tube defects.

Classification

Birth defects are conditions that are present when a baby is born. They can affect the body’s structure and may lead to physical, intellectual, or developmental disabilities. These defects can range from very mild to severe.

Some birth defects are structural issues, like having an extra finger or a split in the roof of the mouth (cleft palate). Others are related to how the body processes nutrients and energy. Many birth defects happen due to a mix of genetic and environmental factors. Examples include heart problems, issues with the nervous system, and problems with the digestive system.

Causes

Birth defects are abnormal conditions present at birth, which can cause disabilities that range from mild to severe. These disabilities may affect the body, thinking ability, or both.

Alcohol exposure

The mother's consumption of alcohol during pregnancy can cause permanent birth defects, including problems with the brain, heart, kidneys, and skeleton. There is no known safe amount of alcohol to consume while pregnant.

Toxic substances

Certain harmful substances, known as teratogens, can cause birth defects. These include some medicines, environmental toxins, and drugs. For example, the medicine thalidomide, which was used in the 1950s, caused severe birth defects in thousands of babies.

Infections

Infections passed from a mother to her baby during pregnancy can also cause birth defects. For example, the rubella virus can cause problems with the eyes, ears, and heart in developing babies.

Malnutrition

Not getting enough nutrients, like folic acid, during pregnancy can lead to birth defects, such as problems with the spine or brain.

Genetics

Genetic problems, such as inheriting abnormal genes or new mutations, can also cause birth defects. These may affect one part of the body or many different areas.

Socioeconomics

Living in poorer neighborhoods with fewer resources can also increase the risk of birth defects, often due to exposure to harmful environments or stress.

Radiation

While radiation exposure, such as from atomic bombs, has not been shown to cause many birth defects in later generations, some studies suggest possible links in certain situations.

Parent's age

Having a baby at an older age, especially for the mother, can increase the risk of certain birth defects. The father's age can also play a role, as older fathers may pass on more genetic mutations.

Prevention

Taking folate supplements can help lower the chance of certain birth defects called neural tube defects. There is some early evidence that a substance called L-arginine might also help prevent a condition where a baby does not grow well inside the womb.

Screening

Main article: Newborn screening

Newborn screening tests help find health problems in babies soon after they are born. These tests started in the 1960s and have grown to check for many different conditions. They use a small blood sample from the baby to look for signs of disorders that can be treated early. Finding these problems quickly allows doctors to start special care, like special food or medicine, to help the baby stay healthy.

Screening can also happen before a baby is born. Doctors can use special scans, like ultrasound, to look at the baby’s development and find any possible issues. These scans can show detailed pictures that help doctors plan the best care for the baby.

Epidemiology

Congenital anomalies, which are conditions present at birth, led to about 632,000 deaths worldwide in 2013. The most common causes of death were congenital heart defects and neural tube defects.

Studies show that some birth defects are more common in boys or girls. For example, pyloric stenosis is more common in boys, while congenital hip dislocation is more common in girls. About 3% of newborns have a major physical anomaly, which can affect their appearance or how their body works. These anomalies are a leading cause of infant deaths in the United States. Each year, around 6,000 babies are diagnosed with Down syndrome, and about 7,000 are born with a cleft palate, cleft lip, or both.