About Birth Defects

Key points

  • Birth defects are structural changes that are present at birth and can range from mild to serious conditions.
  • We don't know what causes most birth defects, but we do know that some things might increase the chances of having a baby with a birth defect.
  • Babies born with birth defects often need special care and interventions to thrive.
Happy baby with a missing hand from a congenital limb deficiency sitting on a blanket.

What they are

Birth defects are structural changes present at birth that can affect almost any part of the body, such as the heart, brain, or foot. They may affect how the body looks, works, or both.

Language matters‎

While "birth defect" is a medical term, it doesn't mean that an individual is "defective." It refers to health conditions that develop in a baby before birth. In an attempt to be accurate and sensitive, we try to use the specific name of the condition present at birth when possible.

Birth defects can vary from mild to severe. Health outcomes and life expectancy depend on which body part is involved and how it is affected.

Birth defects can occur during any stage of pregnancy. Most birth defects occur in the first 3 months of pregnancy, when the organs of the baby are forming. However, some birth defects do occur later in pregnancy as tissues and organs continue to develop.


Birth defects are common, affecting 1 in every 33 babies born in the United States each year. They are also the leading cause of infant deaths, accounting for 20%, or 1 in 5, of all infant deaths.

Risk factors

For some birth defects, like fetal alcohol spectrum disorder, we know the cause. But for most birth defects, we don't know what causes them. We think most birth defects are caused by a complex mix of factors, including our genes, our behaviors, and our environment. But, we don't fully understand how these factors might work together to cause birth defects.

Known risks

While we have more work to do, we have learned a lot. We know that some things might increase the chances of having a baby with a birth defect, such as:

  • Smoking, drinking alcohol, or taking certain drugs during pregnancy.
  • Having certain medical conditions, such as uncontrolled diabetes.
  • Taking certain medications, such as isotretinoin (used to treat acne).
  • Having someone in your family with a birth defect.
  • Getting certain infections during pregnancy, such as cytomegalovirus or Zika.
  • Having fever greater than 101oF or having elevated body temperature.

The age at which you have a child can also influence the risk for birth defects. Some defects are seen more among young mothers (gastroschisis). The risk for some other defects (chromosomal malformations such as Down syndrome) increases with age.

You can have a baby born with a birth defect if you don't have any of these known risks. And having one of these risk factors does not mean that your baby will have a birth defect.

It is important to talk to your doctor about your health and any risk factors and ways to stay healthy during pregnancy.

Pregnant person and doctor smiling, looking at a tablet in a healthcare office.
Talk to your doctor about staying healthy for you and your baby!

Screening and diagnosis

Prenatal screening tests can identify whether your baby is more or less likely to have certain birth defects. A screening test does not provide a specific diagnosis—that requires a diagnostic test. Certain birth defects might not be diagnosed until after the baby is born. Sometimes, the birth defect is immediately seen at birth. For other birth defects, including some heart defects, the birth defect might not be diagnosed until later in life.

Living with birth defects

Babies born with birth defects often need special care and interventions to survive and to thrive. State birth defects tracking programs provide one way to identify and refer children as early as possible for services they need. If your child has a birth defect, you should ask his or her doctor about local resources and treatment.

Many children living with these conditions require care from a variety of specialists and support services. Children and their parents can benefit from the medical home approach to care. This personalized approach allows healthcare providers and families to work together to make sure medical and nonmedical needs are met. Coordinated care can lead to an improved patient and family experience, more consistent care, and reduced healthcare costs.

Concerned about development? Act early!‎

Children born with birth defects can often benefit from early intervention services. Use these resources to find Early Intervention resources in your state.