Birth Defects


According to the Centers for Disease Control and Prevention, one out of every 33 babies in the United States is born with some type of abnormality that developed in utero (CDC). Birth defects can be minor or severe, and they can affect appearance, organ function, and physical or mental development. Most birth defects are present within the first three months of pregnancy, when the organs are forming. Some birth defects are harmless, while others require long-term medical treatment. Severe birth defects are the leading cause of infant death in the United States, accounting for one out of every five deaths.

What Causes Birth Defects?

Birth defects can be genetic, a result of lifestyle choices and behaviors, exposure to certain medicines and chemicals, or a combination of these factors. However, the exact cause of certain birth defects is often unknown.


The mother or father may pass on genetic abnormalities to a baby. These defects are established at conception and often cannot be prevented. A defect may be present throughout the family history of one or more parent. Genetic defects can also be carried in a familys genetic code for generations undetected, and some defects occur only when two healthy parents unknowingly pass along abnormal genes.

Nongenetic Causes

The cause of some birth defects can be difficult or impossible to identify. Certain behaviors, like smoking, drug, and alcohol use greatly increase the risk of defects. Other factors, such as exposure to environmental toxins, medications, or infections also increase risk. Women with pre-existing medical conditions, such as diabetes, are at higher risk of having a child with a birth defect.

Who Is at Risk for Birth Defects?

All pregnant women have some risk of delivering a child who suffers from a birth defect. Risk increases under any of the following conditions:

  • family history of birth defects or other genetic disorders
  • drug use, alcohol consumption, or smoking during pregnancy
  • advanced maternal age of 35 years or older
  • inadequate prenatal care
  • untreated infections or viruses, including sexually transmitted infections

Common Birth Defects

There are thousands of known birth defects, which are typically classified as structural or metabolic. Structural defects are when a specific body part is missing or formed incorrectly. The most common structural defects are:

  • heart defects
  • cleft lip or palate
  • spina bifida
  • clubfoot

Metabolic defects occur when there is an abnormality in a childs genes or chromosomes. The most common types of these defects include Down syndrome, sickle cell disease, and cystic fibrosis.

What Are the Symptoms of Birth Defects?

Some children experience physical problems associated with specific birth defects, however many children show no visible abnormalities and defects can go undetected for months or years after the child is born. The most common defects may bring on any of the following symptoms:

  • delays in meeting developmental milestones
  • feeding problems
  • difficulty breathing
  • failed newborn hearing test
  • seizures

Diagnosing Birth Defects

Prenatal anatomy ultrasounds may diagnose certain birth defects in utero. More in-depth screening options such as blood tests and amniocentesis (taking a sample of the amniotic fluid) may be offered to pregnant women who have higher-risk pregnancies due to family history, advanced maternal age, or other known factors. Prenatal screening may falsely identify defects, and some defects may go undetected. Most birth defects can be diagnosed with certainty at birth. Procedures for diagnosing birth defects may include physical examination, blood tests, and hearing tests.

Treating Birth Defects

Treatment options vary by type of defect and level of severity. Some birth defects can be corrected prior to birth or shortly thereafter. Other defects may affect a child for his or her entire life. Severe defects such as cerebral palsy or neural tube (the structure that becomes a babys brain and spinal cord) defects can cause long-term disability or death. Mild defects such as color blindness or minor cosmetic abnormalities may be stressful but do not typically affect overall quality of life.


Drug regimens may be used in lieu of surgery to treat some types of defects, or to reduce complications from certain defects. In some cases medication may be prescribed to the mother in an attempt to correct an abnormality before birth.


Operations on affected organs may correct defects or mitigate harmful symptoms. Children or adults who have physical birth defects may undergo plastic surgery for either cosmetic or health benefits.

Home Care

Parents may be instructed to follow specific instructions for feeding, bathing, and monitoring an infant with a birth defect.

Ways to Lower Your Childs Risk for Birth Defects

Women who anticipate becoming pregnant should start taking folic acid supplements prior to conception and continue taking a physician-recommended dose as part of a prenatal vitamin throughout pregnancy. Folic acid can prevent serious defects of the spine and brain as well as some other types of birth defects.

Women should avoid alcohol, drugs, and tobacco during and after pregnancy. Some otherwise safe medications and vaccines can cause serious birth defects when taken by pregnant women. Talk to your doctor about any medications (including over-the-counter drugs and supplements) you may be taking, and which vaccines are necessary. Maintaining a healthy weight helps reduce risk of complications during pregnancy, and women with pre-existing conditions, such as diabetes, should take special care to manage their health.

Pregnant women should attend regular prenatal appointments with a healthcare professional. If your pregnancy is considered high-risk, additional screening may be able to identify defects so they can be treated as soon as possible.

Genetic Counseling

A genetic counselor can advise couples with family histories of birth defects. A counselor can be helpful whether you are thinking about children or already expecting. This health professional can help determine the likelihood that your baby will be born with defects by evaluating family history and medical records. Genetic counselors may order tests to analyze the genes of the mother, father, and baby as well.