Tracking Birth Conditions and Outcomes

Birth defects are problems that develop while a fetus is growing during pregnancy. These problems can cause physical and mental disabilities, and may result in death.

There are thousands of different birth defects. Most occur in the first three months of pregnancy. The most common are heart defects, hypospadias, cleft lip and cleft palate, Down Syndrome and Spina Bifida.

Birth defects are estimated to affect more than 120,000 children in the United States every year. Babies born with birth defects have a greater chance of illness and long-term disability than babies without birth defects. Babies with birth defects are also more likely to be born preterm (before the 37th week of pregnancy) than babies without birth defects. Birth defects account for approximately 30% of all pediatric hospital admissions. Most birth defects are thought to be caused by a complex mix of genetic, behavioral, and environmental factors, although, for many birth defects, exactly how these factors work together is unclear.

The Relationship between the Environment and Birth Defects

Although some research on how environmental hazards might be associated with birth defects has been done, much more work is needed to understand the relationship between the environment and birth defects. Doctors and public health researchers know how some birth defects happen and in some cases can make recommendations to help prevent them. But the causes of many other birth defects remain unclear. Analyzing data about when and where birth defects happen will help scientists understand whether these defects might be related to the environment.

Environmental Factors Associated with Birth Defects

It is not clear how many birth defects are related to exposure to environmental hazards, such as pollution, toxic chemicals, and ionizing radiation. Some endocrine-disrupting chemicals, including polychlorinated biphenyls (PCBs), chlorine-related dioxins, and pesticides, have been linked to nervous system defects and developmental problems such as reduced muscle tone and response. Exposure to disinfection by-products in drinking water, such as trihalomethanes (THMs), may also increase the risk of some types of birth defects which affect the brain and spinal cord, the urinary tract, and the heart. In addition, living near a hazardous waste site has been identified as a possible risk factor for birth defects, such as neural tube defects which are defects in the development of the brain and spinal cord, as well as heart and blood vessel defects.

In addition to environmental hazards, other factors linked to birth defects include:

  • Personal Behavior – Take steps to control any medical condition (obesity, diabetes, seizures, etc.) before getting pregnant and make healthy choices.
  • Genetics - Some birth defects are caused by genetic problems. Sometimes, these birth defects run in families, but other times they will occur even when there is no one else in the family who has this problem. If you have concerns that your baby may be at risk of having a genetic abnormality, you can talk with a clinical geneticist or genetic counselor.
  • Mother's Age - Women over the age of 35 years have a higher chance of having a child with Down syndrome than women who are younger. Read more about Down syndrome. Teenage mothers are more likely to have a baby born with gastroschisis, a defect in the abdominal wall.

Reducing Risk of Birth Defects

You can do many things to help yourself have a healthy pregnancy and a healthy baby:

  • Plan your pregnancy
    • Control any medical condition (obesity, diabetes, seizures, etc.) before getting pregnant.
    • See your health care provider before you become pregnant.
    • Take a vitamin with 400 micrograms of folic acid daily before and during pregnancy.
  • Take care of yourself
    • Avoid alcohol, tobacco, and illicit drugs.
    • Avoid contact with chemicals and other things in the home and workplace that may harm an unborn baby.
    • Eat a well-balanced diet.
    • Exercise moderately.
    • Get plenty of rest.
    • 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 identify 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 you can take some actions that increase your chance of having a healthy baby. Many birth defects happen very early in pregnancy, sometimes before you might know that you are pregnant. Remember that about half of all pregnancies in the United States are not planned.
    • Talk with your health care provider before taking any over-the-counter drugs.