skip navigation
Health EffectsEnvironmental HazardsTopics A-ZTopics A-ZPublicationsResourcesFrequently Asked QuestionsAbout Us
NH Environmental Public Health Tracking Program
Birth Defects

Birth defects are estimated to affect more than 120,000 children in the United States every year. About 3% of babies, or 1 of every 33, are born with a structural birth defect. Birth defects are one of the leading causes of infant deaths and illness. 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.

More research is needed to study the subtle links between environmental hazards and birth defects, which is why birth defects are an important part of the Environmental Public Health Tracking Network. In summary, birth defects are expensive and burdensome conditions that need to be reduced through better tracking, research and prevention. The risk of certain birth defects can be reduced by following the recommendations below.

Birth Defects and the Environment

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. Analyzing data about when and where birth defects happen will help scientists understand whether these defects might be related to the environment.


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, and heart and blood vessel defects.

To Have a Healthy Pregnancy and a Healthy Baby

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

Birth Defects Data

The EPHT Program is tracking the total number of cases for 12 specific birth defects:

For more information about birth defects data for environmental public health tracking

For more information on birth defects:

Environmental Public Health Tracking Program
NH Department of Health and Human Services, Division of Public Health Services
29 Hazen Drive, Concord, NH 03301
Tel: (603) 271-4988 800-852-3345 ext.4988

copyright 2009. State of New Hampshire