Birth Defects: What are, Types & Causes

Birth Defects: What are, Types & Causes

What are birth defects?

Birth defects are abnormal growth changes in your body that happen during fetal development. These changes can affect any part of your child’s body. A healthcare provider can detect birth defects during pregnancy, after your baby is born or later during your child’s life. Most providers identify a birth defect within your child’s first year. Not all birth defects are visible.

While some birth defects can be life-threatening, the impact they have on your child’s life varies based on their diagnosis. Some birth defects only change your child’s appearance, while others can affect the way they think, move and function.

What are examples of birth defects?

Some of the most common birth defects include, but aren’t limited to, the following:

  • A cleft lip and/or cleft palate.
  • Bone growth abnormalities that cause short stature, missing limbs or scoliosis.
  • Congenital heart conditions.
  • Chromosome abnormalities (Down syndrome).
  • Clubfoot.
  • Fetal alcohol syndrome.
  • Sickle cell anemia.

How common are birth defects?

Birth defects are common. Every four and a half minutes, a baby in the United States is born with a birth defect. This equals 1 out of every 33 babies born or 120,000 babies each year.

Is it OK to use the term “birth defect”?

“Birth defect” is a medically accurate term to describe structural changes to a person’s body that happen during fetal development. It’s OK to refer to a condition as a birth defect. It’s never OK to call people “defective” if they have a birth defect. Changes to their bodies don’t define who they are. It’s important to avoid talking in a negative or unkind way when you talk about birth defects or people who have birth defects. If you’re not comfortable using the term “birth defect,” other options include:

  • Congenital (present at birth) abnormalities.
  • Congenital conditions.
  • Physical malformations.

Symptoms and Causes

What are the signs and symptoms of birth defects?

Symptoms of birth defects range from mild to severe. They can affect almost any part of the body like your bones and organs.

During pregnancy, a healthcare provider will use screening tests to look for signs of birth defects. Signs of a birth defect during pregnancy can include:

  • Protein levels from a blood test that are higher or lower than expected.
  • Extra fluid behind a fetus’ neck during an ultrasound.
  • Structural abnormalities of a fetus’ internal organs, like the heart, during a fetal echocardiogram.

Some birth defects won’t be present until a child is born or shortly after birth. Common signs and symptoms of birth defects among infants and toddlers include:

  • An abnormal rhythm of their heart.
  • Difficulty breathing on their own.
  • Not responding to their name being called or loud noises.
  • Their eyes don’t follow you or an object in front of them.
  • Difficulty feeding.
  • Their head, face, eyes, ears or mouth have unique characteristics.
  • They don’t meet developmental milestones for their age.
  • Irritability.

While this isn’t a complete list of the signs and symptoms of birth defects, contact your child’s healthcare provider if something doesn’t seem right or if you notice any of the signs or symptoms listed above.

What causes birth defects?

There are several possible causes of birth defects, including:

  • Genetic changes.
  • A side effect of a medication.
  • Substance or chemical exposure.
  • Pregnancy complications.

These causes occur during fetal development. Many are out of your control and there’s nothing you can do to prevent them.

When a fetus is growing in your uterus, it goes through two major stages of development after conception. The embryo stage occurs during the first 10 weeks after conception. Most of the fetus’ major body systems and organs form during this time. The second, or fetal stage, is the remainder of the pregnancy. This fetal period is a time of organ growth and the growth of the fetus in general.

A developing fetus is most vulnerable to birth defects during the embryo stage when organs are developing. For example, substance or chemical exposure can cause the greatest damage to a fetus between two and 10 weeks after conception.

Medical science has identified the cause of about 30% of birth defects. That means about 70% remain without a straightforward cause. As many as 50% to 70% of birth defects are random, and their cause remains unknown.

Genetics and birth defects

About 20% of birth defects occur as a result of genetic factors.

The average human body cell contains 46 chromosomes, and each chromosome contains thousands of genes. Each gene contains a blueprint that controls the development or function of a particular body part. Among people who have either too many or too few chromosomes, their cells receive a scrambled message on how to develop and function.

Chromosome changes occur when there are:

  • Too many chromosomes: Down syndrome is an example of a condition caused by too many chromosomes. During cell division, individuals with Down syndrome have an extra copy of chromosome 21.
  • Not enough chromosomes: Turner syndrome is an example of a chromosomal condition where a person is born without part of or missing an entire X sex chromosome.
  • Deleted chromosomes: A genetic change can affect the number of chromosomes in your DNA. For example, people diagnosed with Prader-Willi syndrome are missing genetic information on chromosome 15.
  • Relocated chromosomes: Chromosomes can move within your DNA to a numbered seat other than their own. This is known as translocation. An example of translocation is rare cases of Smith-Magenis syndrome.

Some birth defects are inherited. This means that you can develop a condition that runs in your biological family. Other conditions occur randomly (sporadically) and you won’t have a history of the condition in your family.

Medications and birth defects

Some medications can have an impact on developing fetuses and can cause birth defects. Common medications that can lead to birth defects include:

  • Isotretinoin (Accutane® or Roaccutane®).
  • Antiepileptic medications (valproic acid).
  • Lithium.
  • Warfarin.

If you’re pregnant or plan on becoming pregnant, talk to a healthcare provider about the medications and supplements you currently take and the side effects of medications they prescribe to you. They’ll let you know if it’s safe to continue taking certain medications. Don’t stop taking the medication until your provider approves it.

Substance or chemical exposure and birth defects

Substances and chemicals within a person’s environment can affect the development of a fetus and lead to birth defects. Common substances or chemicals that can lead to birth defects include:

  • Alcohol.
  • Addictive substances like caffeine, prescription drugs and non-medical drugs.
  • Pesticides or herbicides.
  • Pollution.

Birth defects are common in certain areas of the world where people used dangerous pesticides and herbicides. An example of this is Agent Orange, an herbicide (plant-killing chemical) used during the Vietnam conflict from 1962 to 1971. This herbicide is no longer available on the market due to its harmful and deadly effects.

Pregnancy complications and birth defects

Some complications that happen during pregnancy can lead to birth defects. These complications are usually outside of the birthing parent’s control and it can be a very emotional experience.

Examples of pregnancy complications that can lead to birth defects include:

  • Uterine constraint: The amniotic sack that holds the fetus breaks during pregnancy. This can lead to amniotic band syndrome and possible limb amputations.
  • Lack of amniotic fluid: There isn’t enough fluid that surrounds the fetus in your uterus. This can cause pressure on the fetus and can damage its lungs (pulmonary hypoplasia).
  • Infection: Certain infections, like toxoplasmosis and cytomegalovirus, can affect a developing fetus.

To prevent these complications, you can talk with a healthcare provider about ways to keep yourself and the developing fetus healthy during pregnancy.

What are the risk factors for birth defects?

Certain factors or health conditions can put you more at risk of having a child with a birth defect. These include but aren’t limited to:

  • Diabetes.
  • Obesity.
  • Age of a birthing parent (over 35 years).
  • A genetic condition runs in your biological family history (genetic predisposition).
  • Substance-use disorder.
  • Taking certain medications.

Your healthcare provider can help you manage any underlying conditions. They can also offer testing to assess your risk of having a child with a genetic condition.

Diagnosis and Tests

How are birth defects diagnosed?

A healthcare provider can diagnose a birth defect during pregnancy, after your child is born or later during their life when symptoms become apparent. Testing can confirm a diagnosis.

What tests diagnose birth defects?

During pregnancy, you may choose to get screening tests for birth defects and genetic conditions with ultrasounds or blood tests. If a screening test shows something abnormal, your provider will recommend a diagnostic test. First-trimester screenings check for abnormalities with the fetal heart and chromosomal conditions such as Down syndrome.

Screening tests include:

  • Blood screen: Blood tests can measure protein levels or circulating free fetal DNA in the birthing parent’s blood. Abnormal results can indicate an increased risk of a fetal chromosomal condition.
  • Ultrasound: An ultrasound looks for extra fluid behind the fetus’ neck. It could be a sign of a heart condition or chromosomal condition.

Second-trimester screenings check for problems with the structure of the fetus’ anatomy. The tests include:

  • Serum screen: Blood tests in the second trimester can screen for chromosomal conditions and/or spina bifida.
  • Anomaly ultrasound: An anomaly ultrasound checks the size of the fetus and checks for birth defects.

If a screening test is abnormal, a healthcare provider may offer more tests. Diagnostic tests are also offered to people with higher-risk pregnancies. The tests include:

  • Fetal echocardiogram: This is a focused ultrasound of the fetal heart. Diagnostic tests can’t detect all heart conditions before birth.
  • Fetal MRI: This imaging test examines the fetal brain or nervous system.
  • Chorionic villus sampling: Your healthcare provider will collect a very small piece of the placenta for this test. They’ll examine it for chromosomal or genetic conditions.
  • Amniocentesis: Your healthcare provider will collect a small amount of amniotic fluid. A provider will test cells for chromosomal conditions and genetic changes. Amniocentesis can also test for certain infections such as cytomegalovirus (CMV).

Healthcare providers may diagnose certain birth defects after your baby is born. A provider can diagnose some conditions immediately, like a cleft lip. Other conditions will receive a diagnosis later during childhood or adulthood. Keep an eye on your baby’s health and report any symptoms to your child’s healthcare provider.

Management and Treatment

How are birth defects treated?

Treatment depends on the diagnosis. It usually focuses on reducing symptoms or repairing any structural abnormalities and could include:

  • Surgery.
  • Medications.
  • Physical therapy.
  • Using devices like hearing aids, glasses, a brace or a wheelchair.
  • Educational support in school (special education).

Is there a cure for birth defects?

In general, there isn’t a cure for birth defects, especially genetic conditions. Treatment can help lessen your child’s symptoms and reduce their risk of life-threatening complications if symptoms are severe.


Can birth defects be prevented?

You can’t prevent most types of birth defects. There are steps you can take to promote a healthy pregnancy, including:

  • See your healthcare provider consistently.
  • If you’re trying to conceive, or if you are sexually active and not using contraception, take a prenatal vitamin with 400 mcg of folic acid.
  • Contact your healthcare provider immediately if you think you’re pregnant.
  • Don’t drink alcohol.
  • Talk to your healthcare provider about any medications and supplements you’re taking.
  • Avoid taking any drugs not prescribed by a provider.

Outlook / Prognosis

What can I expect if my child has a birth defect?

Birth defects are complicated and they can be very emotional. There also isn’t a cure or a way to prevent most birth defects, which can be frustrating and scary.

If your child receives a diagnosis, your mind may flood with questions. Healthcare providers, medical specialists and genetic counselors are available to help you understand more about the birth defect and how you can help your child.

Remember that birth defects are common. Most causes are out of your control and happen randomly. There’s no preventive measure to protect your child from every type of birth defect. But you can love, advocate and care for your child, which are some of the greatest gifts you can give them.

If you’re a parent of a child with a birth defect, you should schedule appointments with your child’s healthcare provider regularly. You and their healthcare provider should thoroughly discuss possible causes, testing, treatment and referrals to specialists and support groups. If you have any questions, reach out to your child’s care team for assistance.

Living With

When should I see a healthcare provider?

Visit a healthcare provider if your child shows any signs of birth defects. It’s especially important to keep track of your child’s developmental milestones, like when they take their first steps, to make sure they’re on track for their age. If your child misses any milestones, contact their provider.

When should I go to the ER?

Visit the emergency room if your child shows signs of distress like:

  • Difficulty breathing.
  • A blue, pale or gray tone to their skin.
  • Yellowing of the whites of their eyes or skin.
  • An abnormal heartbeat.
  • Difficulty waking up.
  • Not feeding.

What questions should I ask my doctor?

  • What caused my child’s birth defect?
  • Do I need to have a cesarean section?
  • What are the treatment options to help my child?
  • Are there side effects of the treatment?
  • Are there symptoms I should look out for?
  • Can you recommend any support groups for families?

Additional Common Questions

Are dimples a birth defect?

Dimples aren’t a birth defect. Dimples are indentations in your cheeks. You notice dimples when you smile. While dimples can run in families, they’re hereditary, but not considered a growth abnormality.

A note from Cleveland Clinic

The very last thing an expectant parent wants to hear is that there’s something wrong with the fetus or with their infant. You can’t prevent most birth defects, but you can take steps before and during your pregnancy to reduce the risk of birth defects. Remember, you’re not alone. Your healthcare providers understand the challenges of raising a child who has a birth defect. They’ll share information about screening tests, medications and other ways to help your child reach their full potential.


Most read