What to Know About Birth Defects

Medically Reviewed by Poonam Sachdev on November 09, 2021

The term birth defect sounds like every parent’s worst nightmare. It suggests that something terrible is wrong with your new baby. In reality, a birth defect is a medical term that means that your child is born with some physical difference. 

Birth defects are common and affect thousands of babies every year. Certain birth defects may present major challenges for a family as the child grows up. There are also minor birth defects that don’t affect a child’s quality of life.

How Common Are Birth Defects?

Experts estimate that in the United States, a baby is born with a birth defect every four minutes. Birth defects affect 120,000 babies each year.

Some birth defects are obvious right after birth. Others are diagnosed during the first year of a child’s life. Some differences take much longer to appear. For example, scoliosis is a difference in bone development that leads to a curve of the spine. You may not know your child has it until they are close to puberty.

What Are the Types of Birth Defects?

There are a wide variety of birth defects, and they can affect different body parts. Some are obvious, and you can see them when you look at a child. Your child might have a visible difference, such as a cleft lip, a limb difference, or a birthmark on their skin.

Examples of birth defects include: 

  • Limb differences: missing limbs, shortened limbs, extra fingers or toes
  • Down syndrome: a chromosomal condition that affects physical and cognitive development
  • Hearing loss: from mild to profound deafness
  • Diaphragmatic hernia: the intestines bulge into an opening in the diaphragm
  • Spina bifida: the spinal column doesn’t properly close during fetal development, resulting in physical disabilities
  • Port-wine birthmark: a reddish mark that appears on the skin, often on a child’s face

Other birth defects affect internal organs. For example, many babies are born with a small hole between the chambers of their hearts. Some babies have chemical imbalances like phenylketonuria, which affects how they metabolize certain amino acids.

There are also issues that may not be evident until a year more after birth when you notice the child isn't growing or developing typically. Your doctor will examine your baby to determine the extent of their differences and figure out the cause. 

What Are the Causes of Birth Defects?

There is often no explanation for a birth defect. They all occur while the baby is still developing in the womb. They usually arise during the first three months of pregnancy while all the organs are developing. Some defects may occur later in pregnancy, such as limb differences caused by the amniotic sac constricting a limb and affecting growth. 

About 20% of birth defects are due to genetic factors, including:

  • Chromosomal abnormalities
  • Single-gene defects
  • Multifactorial issues

Birth defects can run in families. Others are spontaneous, meaning a gene mutates for no known reason. 

Some birth defects are caused by exposing the fetus to drugs or alcohol during pregnancy. Some medical conditions such as uncontrolled diabetes can increase the risk of your baby having birth defects. Babies of older parents have a higher incidence of birth defects. 

It may be possible to diagnose certain birth defects before a baby is born. Some differences can be seen during ultrasounds. Your doctor may detect other issues through blood tests or genetic testing. 

Is There Treatment for Birth Defects?

The treatment for birth defects depends on your baby’s condition. Down syndrome is lifelong, and your child will require educational accommodations and medical care as they grow up. Other conditions, such as a cleft lip, can be repaired with surgery when a child is very young.

Some rare conditions cannot be treated. Syndromes like Tay-Sachs disease or certain neurological issues such as anencephaly mean that all doctors can offer is management of the condition. 

If your child is born with a birth defect, your doctor will talk to you about treatment or management options.

Can You Prevent Birth Defects?

Many birth defects cannot be prevented. There is nothing parents could have done to change how their baby developed. No one is to blame for your child’s differences.

There are general recommendations that parents can follow to have a healthy pregnancy. This may reduce the risk of defects that arise due to issues you can control.

  • Avoid drugs and alcohol while you are pregnant.
  • Talk to your doctor about prescription medications you take before you try to conceive.
  • Eat a healthy diet and follow your doctor’s recommendations for exercise.
  • Take folic acid to prevent neural tube problems in your baby, like spina bifida.
  • Talk to your employers about safety precautions at work.
  • Manage any health conditions you have before and during pregnancy.

Show Sources


American College of Obstetricians and Gynecologists: "Reducing Risks of Birth Defects."

Centers for Disease Control and Prevention: “What are Birth Defects?”

Cleveland Clinic: “Birth Defects.”

March of Dimes: "Birth Defects & Other Health Conditions."

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