Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

Birth Defects and the Environment

It is not clear how many birth defects are related to environmental exposures, such as chemicals, drugs, and ionizing radiation. Some endocrine-disrupting chemicals, including polychlorinated biphenyls (PCBs), dioxins, and pesticides, have been linked to nervous system defects and developmental problems such as reduced muscle tone and response. But, we need more data to make these connections clearer.

Living near a hazardous waste site has been identified as a possible risk factor for birth defects including: spina bifida, cleft lip or palate, gastroschisis, hypospadias, chromosomal congenital anomalies such as Down syndrome, and some heart and blood vessel defects. Exposure to disinfection by-products in drinking water such as trihalomethanes, or THM, may increase the risk of some types of birth defects which affect the brain and spinal cord, the urinary tract, and the heart.

Although some research on how environmental hazards might cause birth defects has been done, much more work is needed to understand the relationship between the environment and birth defects. Doctors and public health scientists 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 are unclear.

Sharing data about when and where birth defects happen will help scientists understand whether these defects might be related to the environment. Gaining this understanding is one of the main reasons why birth defects are part of the National Environmental Public Health Tracking Network.

Learn more about the Birth Defect Indicators on the Tracking Network

 Top of Page
TOP