Birth Defects

Frequently Asked Questions

What is a birth defect? Which are most common? Learn answers to these and other frequently asked questions listed below...

What is a birth defect?

A birth defect is a problem that happens while the baby is developing in the mother’s body. Most birth defects happen during the first 3 months of pregnancy.

A birth defect may affect how the body looks, works, or both. It can be found before birth, at birth, or anytime after birth. Most defects are found within the first year of life. Some birth defects (such as cleft lip or clubfoot) are easy to see, but others (such as heart defects or hearing loss) are found using special tests (such as x-rays, CAT scans, or hearing tests). Birth defects can vary from mild to severe.

Some birth defects can cause the baby to die. Babies with birth defects may need surgery or other medical treatments, but, if they receive the help they need, these babies often lead full lives.

What are the most common birth defects?

One of every 33 babies is born with a birth defect. A birth defect can affect almost any part of the body. The well being of the child depends mostly on which organ or body part is involved and how much it is affected.

Many birth defects affect the heart. About 1 in every 100 to 200 babies is born with a heart defect. Heart defects make up about one-third to one-fourth of all birth defects. Some of these heart defects can be serious, and a few are very severe. In some places of the world, heart defects cause half of all deaths from birth defects in children less than 1 year of age.

Other common birth defects are “neural tube defects,” which are defects of the spine (spina bifida) and brain (anencephaly). They affect about 1 of 1,000 pregnancies. These defects can be serious and are often life threatening. They happen less often than heart defects, but they cause many fetal and infant deaths.

Birth defects of the lip and roof of the mouth are also common. These birth defects, known as “orofacial clefts,” include cleft lip, cleft palate, and combined cleft lip and cleft palate. Cleft lip is more common than cleft palate. In many places of the world, orofacial clefts affect about 1 in 700 to 1,000 babies.

Some birth defects are common but rarely life threatening, though they often require medical and surgical attention. “Hypospadias,” for example, is a fairly common defect found in male babies. In babies with hypospadias, the opening of the urethra (where urine comes out) is not at the tip of the penis but on the underside. Treatment depends on how far away from the tip the opening is and can involve complex surgery. This defect is rarely as serious as the others listed above, but it can cause great concern and sometimes has high medical costs. It rarely causes death.

These are only some of the most common birth defects. Two final points are worth noting. First, genetic conditions, though not mentioned so far, also occur often. Down syndrome, for example, is a genetic condition that affects about 1 in 800 babies, but it affects many more babies who are born to older women. Second, a woman who is pregnant may miscarry a baby (fetus) early, before it is time for the baby to be born. This often happens when the fetus has a severe birth defect. To know the true impact of birth defects and how often they occur, we not only need to look at babies born but also, if possible, look at all pregnancies.

What is my chance of having a baby with a birth defect?

In the United States, about 3% of babies are born with birth defects. Some women have a higher chance of having a child with a birth defect. Women over the age of 35 years have a higher chance of having a child with Down syndrome than women who are younger. If taken when a woman is pregnant, certain drugs can increase the chance of birth defects. Also, women who smoke and use alcohol while pregnant have a higher risk of having a baby with certain birth defects. Other women have a higher chance of having a baby with a birth defect because someone in their family had a similar birth defect. To learn more about your risk of having a baby with a birth defect, you can talk with a genetic counselor. (To find a genetic counselor, see Where can I find a geneticist or genetic counselor?) Also, to reduce your chances of having a baby with a birth defect, talk with your health care provider about any medicines that you take, do not drink alcohol or smoke, and be sure to take 400 micrograms of the B vitamin folic acid every day. It is the amount of folic acid found in most multivitamins.

Do genetic factors play a role in causing birth defects?

Yes, in some but not all cases. Changes in the genes can cause certain birth defects in infants. Genes tell each cell in the body how to combine with other cells to form parts of the body. For example, genes tell certain cells to make the heart, the kidneys, or the brain, and they tell other cells to make our physical features, like green eyes or brown hair. Genes also tell the cells how to work in the body. Genes give instructions for cells in our heart to beat, our stomach to digest food, our muscles to push and pull, and our brain to think.

Genes combine with many other genes to make chromosomes. Changes in single genes, groups of genes, or entire chromosomes can sometimes cause birth defects. These genetic changes might happen only in the infant, or they might pass down from one or both parents. Sometimes, there are other relatives in the family with the same birth defect, but not always.

Factors other than genetics can also increase the chance of having a baby with a birth defect. (See Does alcohol cause birth defects? Does smoking cause birth defects? Do illegal drugs cause birth defects?). In some cases, the mother or baby has genes that are easily affected by factors outside the body that cause birth defects. In this case, genes and environment work together to cause a birth defect.

What causes birth defects?

We do not know what causes most birth defects. Sometimes they just happen and are not caused by anything that the parents did or didn't do. Many parents feel guilty if they have a child with a birth defect even if they did everything they could to have a healthy child. If you have a child with a birth defect, it might be helpful to talk with other parents who have had a child with the same condition (See How can I get in touch with parents of a child with the same birth defect as my child?) Sometimes the causes of birth defects are figured out after the baby is born. Whenever possible, it is important to know what you can do for a better chance of having a healthy child in the future. Some actions might increase the chances of having a baby with a birth defect. The questions and answers that follow talk about some of these known risks.

Does alcohol cause birth defects?

What are FAS and FASDs?

Prenatal exposure to alcohol can cause a range of disorders, known as fetal alcohol spectrum disorders (FASDs). One of the most severe effects of drinking during pregnancy is fetal alcohol syndrome (FAS). FAS is one of the leading known preventable causes of mental retardation and birth defects. If a woman drinks alcohol during her pregnancy, her baby can be born with FAS, a lifelong condition that causes physical and mental disabilities. FAS is characterized by abnormal facial features, growth deficiencies, and central nervous system (CNS) problems. People with FAS might have problems with learning, memory, attention span, communication, vision, hearing, or a combination of these. These problems often lead to difficulties in school and problems getting along with others. FAS is a permanent condition. It affects every aspect of an individual’s life and the lives of his or her family.

Fetal alcohol spectrum disorders (FASDs) is an umbrella term describing the range of effects that can occur in an individual whose mother drank alcohol during pregnancy. These effects include physical, mental, behavioral, and/or learning disabilities with possible lifelong implications. The term FASDs is not intended for use as a clinical diagnosis.

FASDs include FAS as well as other conditions in which individuals have some, but not all, of the clinical signs of FAS. Three terms often used are fetal alcohol effects (FAE), alcohol-related neurodevelopmental disorder (ARND), and alcohol-related birth defects (ARBD). The term FAE has been used to describe behavioral and cognitive problems in children who were prenatally exposed to alcohol, but who do not have all of the typical diagnostic features of FAS. In 1996, the Institute of Medicine (IOM) replaced FAE with the terms ARND and ARBD. Children with ARND might have functional or mental problems linked to prenatal alcohol exposure. These include behavioral or cognitive abnormalities or a combination of both. Children with ARBD might have problems with the heart, kidneys, bones, and/or hearing.

All FASDs are 100% preventable—if a woman does not drink alcohol while she is pregnant.

How common are FAS and FASDs?

The reported rates of FAS vary widely. These different rates depend on the population studied and the surveillance methods used. CDC studies show FAS rates ranging from 0.2 to 1.5 per 1,000 live births in different areas of the United States. Other FASDs are believed to occur approximately three times as often as FAS.

Click here to learn more about CDC FAS surveillance activities.

What are the characteristics of children with FAS and other FASDs?

FAS is the severe end of a spectrum of effects that can occur when a woman drinks during pregnancy. Fetal death is the most extreme outcome. FAS is a disorder characterized by abnormal facial features and growth and central nervous system (CNS) problems. If a pregnant woman drinks alcohol but her child does not have all of the symptoms of FAS, it is possible that her child has another FASD, such as alcohol-related neurodevelopmental disorder (ARND). Children with ARND do not have full FAS but might demonstrate learning and behavioral problems caused by prenatal exposure to alcohol. Examples of these problems are difficulties with mathematical skills, difficulties with memory or attention, poor school performance, and poor impulse control and/or judgment.

Children with FASDs might have the following characteristics or exhibit the following behaviors:

• Small size for gestational age or small stature in relation to peers
• Facial abnormalities such as small eye openings
• Poor coordination
• Hyperactive behavior
• Learning disabilities
• Developmental disabilities (e.g., speech and language delays)
• Mental retardation or low IQ
• Problems with daily living
• Poor reasoning and judgment skills
• Sleep and sucking disturbances in infancy

Children with FASDs are at risk for psychiatric problems, criminal behavior, unemployment, and incomplete education. These are secondary conditions that an individual is not born with but might acquire as a result of FAS or a related disorder. These conditions can be very serious, but there are protective factors that have been found to help individuals with FASDs. For example, a child who is diagnosed early in life can be placed in appropriate educational classes and given access to social services that can help the child and his or her family. Children with FASDs who receive special education are more likely to achieve their developmental and educational potential. In addition, children with FASDs need a loving, nurturing, and stable home life to avoid disruptions, transient lifestyles, or harmful relationships. Children with FASDs who live in abusive or unstable homes or who become involved in youth violence are much more likely than those who do not have such negative experiences to develop secondary conditions.

If you think your child might have an FASD, contact your doctor who might be able to refer you to a specialist who can assess your child.

How can we prevent FASDs?

FASDs are completely preventable—if a woman does not drink alcohol while she is pregnant or could become pregnant. If a woman is drinking during pregnancy, it is never too late for her to stop. The sooner a woman stops drinking, the better it will be for both her baby and herself. If a woman is not able to stop drinking, she should contact her doctor, local Alcoholics Anonymous, or local alcohol treatment center. The Substance Abuse and Mental Health Services Administration has a Substance Abuse Treatment Facility locator. This locator helps people find drug and alcohol treatment programs in their area. If a woman is sexually active and is not using an effective form of birth control, she should not drink alcohol. She could become pregnant and not know it for several weeks or more.

Mothers are not the only ones who can prevent FASDs. The father’s role is also important in helping the mother abstain from drinking alcohol during pregnancy. He can encourage her not drinking alcohol by avoiding social situations that involve drinking and by not drinking alcohol himself. Significant others, family members, schools, health and social service organizations, and communities can also help prevent FASDs through education and intervention.

In February 2005, the U.S. Surgeon General issued an Advisory on Alcohol Use in Pregnancy to raise public awareness about this important health concern. To reduce prenatal alcohol exposure, prevention efforts should target not only pregnant women who are currently drinking, but also women who could become pregnant, are drinking at high-risk levels, and are having unprotected sex.

Does smoking cause birth defects?

A woman who smokes while she is pregnant has a greater chance of having a premature (early) birth, a small baby, or a stillborn baby. If the mother smokes while pregnant, there is also an increased risk of the baby dying during the first year of life. Some types of birth defects have been linked to the mother’s smoking. Birth defects that may be increased when the mother smokes include: cleft lip, cleft palate, clubfoot, limb defects, some types of heart defects, gastroschisis (an opening in the muscles of the abdomen that allows the intestines to appear outside the body), and imperforate anus (there is no opening from the intestines to the outside of the body to allow stool or gas to be passed). Talk with your health care provider about ways to help you quit smoking if you are pregnant or can get pregnant.

Do illegal drugs cause birth defects?

Women who use illegal drugs, or “street drugs,” can have babies who are small, premature, or have other health problems, such as birth defects.

Women who use cocaine while pregnant are more likely to have babies with birth defects of the limbs, gut, kidneys, urinary system, and heart. Other drugs, such as marijuana and ecstasy, may also cause birth defects in babies.

Women should not use street drugs while they are pregnant. It is also important that women not use street drugs after they give birth because drugs can be passed through breast milk and can affect a baby’s growth and development. Talk with your health care provider about ways to help you quit using street drugs before you get pregnant.

Does exposure to the MMR vaccine cause birth defects? Other vaccines?

The MMR is a vaccine for measles, mumps, and rubella. If a woman gets one of these viruses while pregnant, it may cause her to have a miscarriage or to have a baby with birth defects. The MMR, like some other vaccines, is made with viruses that are alive but very weak. Because these viruses are alive, there is a very slight chance that they may cause harm to the baby. For this reason, a woman who may be pregnant should not get an MMR or other vaccine unless she is at high risk of getting a serious illness without it. She should talk about the risks and benefits of getting the vaccine with her doctor. A woman who has just gotten the vaccine and then learns she is pregnant should also talk with her doctor. Vaccines such as those for tetanus and hepatitis are made from dead viruses or parts of dead viruses and do not cause infection in the mother and should not harm the fetus.

When in pregnancy do birth defects happen?

Birth defects happen before a baby is born. Inherited or genetic factors; things in the environment, such as smoking or drinking alcohol or not getting enough folic acid; and a woman’s illness during pregnancy can cause birth defects. Most birth defects happen in the first 3 months of pregnancy, when the organs of the baby are forming. This is the most important stage of development. However, some birth defects happen later in pregnancy. During the last six months of pregnancy, the tissues and organs continue to grow and develop.

Some birth defects can be found before birth. If you want to know more about your risk of having a baby with a birth defect, contact a genetic counselor. See Where can I find a clinical geneticist or genetic counselor?

What can I do to keep germs from harming my baby and me?

Infections: You won’t always know if you have an infection—sometimes you won’t even feel sick. Learn how to help prevent infections that could harm your unborn baby.

What kind of health care provider can help find out what caused my baby’s birth defect?

Birth defects are common in our country. Some birth defects are found before birth, some at the time of birth, and some are found during the first year of life. A few don't show up until the child is older. It is common for parents to want to know what caused their baby’s birth defect. However, the causes for about 70% birth defects are unknown.

A primary care provider (PCP) usually looks at a child who may have a birth defect. The PCP is most often the child’s pediatrician or the family’s general physician. PCPs look for important clues in the child’s first exam for a birth defect. The first exam includes a lot of questions about history, a physical exam, and sometimes testing. The PCP is trying to find a “diagnosis” (name or cause) for the child’s type of birth defect. If a diagnosis cannot be made after the first exam, the PCP may refer the child to a specialist in birth defects and genetics. A clinical geneticist is a doctor with special training to evaluate patients who may have genetic conditions or birth defects. Even if a child sees a specialist, an exact diagnosis may not be reached.

Counseling the family of an infant with a birth defect is a large part of the PCP’s job. PCPs may refer parents to a genetic counselor to help parents learn more about their infant’s condition. A genetic counselor explains the diagnosis, the possible role of genes, and medical aspects of the birth defect. A genetic counselor can talk with parents about their risk of having future children with a birth defect. He or she also talks with parents about how to lessen their chances of having another baby with birth defects. Counseling can help a family adjust to and plan for their newborn.

Who coordinates the health care of my child who has a birth defect?

The PCP usually provides the basic care of a child with a birth defect. The PCP should know about sources of help for the child and the family. Help may include support groups, public health services, and current medical literature. The PCP also coordinates the child’s care. For example, children with birth defects involving their bones may need to see an orthopedist, a doctor trained in problems with the bones. A child with a birth defect involving the brain may need to see a neurologist, who is trained to deal with problems in the brain and nervous system. The PCP may also send the child for special services that will help the child function better. For example, a child with a cleft palate may be sent to a speech therapist, someone with special training who works with people to improve their ability to talk. Another common referral is for physical therapy to improve the child’s strength and movement.

Many children with birth defects have more than one problem and may need one or more specialists. The PCP coordinates the care of a child with a birth defect so that he gets all the special care he needs.

In summary, birth defects are common, but the causes for many birth defects are not known at this time. The PCP is generally the best person to coordinate the special care needed for a child with a birth defect.

What does a genetic counselor do?

A genetic counselor talks with you about birth defects and genetic conditions. Genetic counselors are part of the health care team and have special training to help families learn about birth defects and conditions passed down through a family. They can guide families to other resources for help. They also help families deal with feelings about how these conditions affect their family. People talk about both medical and personal questions during genetic counseling. Genetic counselors ask questions about family history and pregnancy history. They talk with families about tests used to find a condition and, if known, about how to prevent a condition.

There are many reasons to see a genetic counselor. Some people go because of a family history of a genetic condition. Others see a genetic counselor because they have trouble getting pregnant or because they have had several miscarriages or infant deaths. Some women may see a genetic counselor after learning the results of a blood test or because of their age. Still others seek genetic counseling to learn about the effects of being exposed to things like x-rays, chemicals, illness, or drugs while pregnant.

Where can I find a clinical geneticist or genetic counselor?

Your best source is your health care provider. He or she will know about the resources in your area. Also, you can call the nearest university medical school or large medical center. To reach them, call the main telephone number and ask for “genetics.” A Web site that may be helpful is http://www.nsgc.org/. * If you cannot find someone in your area, please contact us (tera@cdc.gov) with your location, and we will help you.

Note: *This site is not a CDC site and will be opened in a new browser window. Use your browser "back" button to return to this site. CDC is not responsible for the content of Web pages found at this link. Links to nonfederal organizations are provided solely as a service to our users. These links do not indicate an endorsement of these organizations by CDC or the federal government.

Where can I get information about my baby's birth defect or genetic condition?

If your child has a birth defect, you should ask his or her doctor about local resources and treatment. Geneticists and genetic counselors are another resource. If you need to know where to find these specialists, see Where can I find a clinical geneticist or genetic counselor?

CDC can give you general information about neural tube defects. For other birth defects, you may contact one of the national groups listed below. These groups have fact sheets or brochures or can direct you to support groups, where you can meet and talk with other parents of children with the same type of birth defect. Many support groups also have brochures and books to help you learn more about birth defects.

Fact Sheets about specific birth defects or genetic conditions

• March of Dimes
• National Organization for Rare Disorders, Inc. (NORD)

Web sites with links to support groups

• Genetic Alliance
• International Clearinghouse for Birth Defects Monitoring Systems
• Mountain States Genetics Network
• Teratology Society
• Texas Birth Defects Monitoring Division
• University of Kansas Medical Center Genetics Education Center

How can I get in touch with parents of a child with the same birth defect as my child?

It is helpful for many parents to have contact with other parents of a child with the same type of birth defect that your child has. Parents of a child with the same birth defect may have learned how to deal with some concerns and questions you have. Often, they can give you hints about good resources for your child’s special needs. They can share what worked best with their child. Talking with them may provide emotional support and ways to help you deal better with issues about your child. These resources may be helpful for you:

• Your child’s health care specialist who deals with other children with birth defects is one of the best sources for contact information about support groups. The health care specialist could be a genetic counselor, a neurologist or neurosurgeon, an orthopedist, a developmental pediatrician, a physical or occupational therapist, and some other specialists. Children’s hospitals in your area may sponsor some groups, too.
• A national organization dealing with your child’s birth defect, such as Spina Bifida Association of America, that has a state or local branch, such as Spina Bifida Association of Georgia, may exist. State or local area March of Dimes offices could also be helpful. United Way offices may be able to point out resources. Look in the phone book or on the Web for phone numbers and addresses.
• Internet searches will most likely result in several Web sites for you to check out. Be careful not to trust all that you read on the Internet. Some Web sites give good information, but others may not. Choose Web sites that are associated with well-known national or regional organizations. There are many Web sites of parents with children who have birth defects. Some may suggest things that don’t “feel” right to you. If you have questions or concerns about anything you read on the Web, be sure to ask your child’s health care specialist about it.

What should I do to have a healthy pregnancy?

• Plan your pregnancy

• See your health care provider before getting pregnant
• Get any medical condition (obesity, diabetes, seizures, etc.) under control before getting pregnant
• Take a vitamin with 400 micrograms of folic acid daily before and during pregnancy

• Take care of yourself

• Get plenty of rest
• Exercise moderately
• Eat a well-balanced diet
• Avoid contact with chemicals and other things in the home and workplace that may harm an unborn baby
• Avoid alcohol, tobacco, and street drugs
• Talk with your health care provider before taking any over-the-counter drugs

If you are planning to get pregnant or you are already pregnant, one of the most important things you can do is see your health care provider. Prenatal (before birth) care can help find some problems early in pregnancy so that they can be monitored or treated before birth. Some problems might be avoided with prenatal care.

Not all birth defects can be prevented, but a woman can take some actions that increase her chance of having a healthy baby. Many birth defects happen very early in pregnancy, sometimes before a woman even knows that she is pregnant. Remember that about half of all pregnancies in the United States are not planned. To see a list of pregnancy tips on “Having a Healthy Pregnancy,” go to http://www.cdc.gov/ncbddd/bd/abc.htm. To see the brochure “What You Can Do To Keep Germs from Harming You and Your Baby,” click here.

What is CDC doing to prevent and help find the causes for birth defects?

CDC does research to try to find the causes of birth defects. Some people at CDC work in a lab doing basic science research to find answers. For example, we may study how chemicals in the air or water or land might harm a developing baby. Others at CDC are “epidemiologists” who look at all types of birth defects. They try to figure out what babies with certain birth defects have in common. They might study people’s genes, their use of certain drugs, or their behaviors. Sometimes parents might be doing something that could harm a future baby. CDC studies how behaviors, like drinking alcohol or taking certain drugs, can harm a baby. We then try to explain to people what they can do, or not do, to try to have a healthy baby. CDC also works closely with doctors and other health care workers, schools, communities, and the media to help prevent birth defects.