Research and Tracking
Accurately tracking birth defects is the first step in preventing them and reducing their effect. Birth defects tracking systems are vital to help us find out where and when birth defects occur and who they affect. This gives us important clues about preventing birth defects and allows us to evaluate our efforts.
We base our research on what we learn from tracking. By analyzing the data collected, we can identify factors that increase or decrease the risk of birth defects and identify community or environmental concerns that need more study. In addition, research helps the Centers for Disease Control and Prevention (CDC) answer critical questions about the causes of many of these birth defects.
What We’ve Learned
We know what causes some birth defects, such as Down syndrome and fetal alcohol syndrome. However, for about two-thirds of birth defects, the causes are unknown.1 Also, we don’t understand well how certain factors might work together to cause birth defects. While there is still more work to do, we have learned a lot about birth defects through past research. For example:
- Taking supplements containing folic acid, a B vitamin, at least 1 month before getting pregnant and during pregnancy lowers the risk of having a baby with serious birth defects of the brain and spine (neural tube defects). For this reason, all women who can become pregnant should take supplements containing 400 micrograms of folic acid every day.
- Drinking alcohol during pregnancy can cause the baby to be born with fetal alcohol spectrum disorders (FASDs). Pregnant women should not drink alcohol any time during pregnancy. Women also should not drink alcohol if they are planning to become pregnant or are sexually active and do not use effective birth control.
- Smoking in the month before getting pregnant and throughout pregnancy increases the chance of premature birth, certain birth defects (such as cleft lip, cleft palate, or both), and infant death. Quitting smoking before getting pregnant is best. However, for women who are already pregnant, quitting as early as possible can still help protect against some health problems.
- Women who are obese when they get pregnant have a higher risk of having a baby with serious birth defects of the brain and spine (neural tube defects) and some heart defects. Helping women to reach a healthy weight before they get pregnant could prevent birth defects.
- Poor control of diabetes in pregnant women increases the chance for birth defects, and might cause serious complications for the mother, too. If a woman with diabetes keeps her blood sugar well-controlled before and during pregnancy, she can reduce the chance of having a baby with birth defects.
- Taking certain medications during pregnancy can cause serious birth defects, but the safety of many medications taken by pregnant women has been difficult to determine. If you are pregnant or planning a pregnancy, you should not stop taking medications you need or begin taking new medications without first talking with your doctor. This includes prescription and over-the-counter medications and dietary or herbal products.
Birth Defects Tracking and Research
The Metropolitan Atlanta Congenital Defects Program (MACDP)
MACDP is a population-based tracking system for birth defects among children born to residents of metropolitan Atlanta. Population-based means that the researchers look at all babies with birth defects who live in a defined study area, which is important to get a complete picture of what is happening within this known population. Established in 1967, MACDP was the nation's first population-based system for active collection of information about birth defects. Active data collection means that committed staff members seek out information about birth defects and continually review medical records at multiple health care facilities in a given geographic area. Information obtained from MACDP is used to understand the characteristics of affected children, learn about other health outcomes associated with birth defects, and provide data for education and health policy decisions leading to prevention of birth defects. The system also serves as a model to help other programs develop and implement new tracking methods.
Learn more about the Metropolitan Atlanta Congenital Defects Program (MACDP) »
State-Based Tracking Systems
CDC funds population-based birth defects tracking systems in 14 US states and territories. The tracking systems use the data to help prevent birth defects and to refer infants and children with birth defects to needed services. Identifying birth defects at a state level also strengthens public health officials' ability to estimate prevalence and evaluate risk factors that are the most important in their community. State-based birth defects tracking programs provide important insights into our continued efforts to prevent birth defects and support families affected by them.
National Birth Defects Prevention Network (NBDPN)
CDC supports and collaborates with the NBDPN. The NBDPN is a group of over 225 individuals working at the national, state, and local levels, who are involved in tracking, researching, and preventing birth defects. The NBDPN serves as a forum for exchanging ideas about preventing birth defects for tracking and researching birth defects, and providing technical support for state and local programs. Established in 1997, the NBDPN assesses the effect of birth defects on children, families, and the health care system. It also identifies risk factors for birth defects. This information can be used to develop strategies to prevent birth defects and to assist families and their providers in preventing other disabilities in children with birth defects.
International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR)
The ICBDSR brings together birth defects programs from around the world with the aim of conducting worldwide tracking and research to prevent birth defects and to improve the lives of people born with these conditions. CDC supports and collaborates with the ICBDSR as a way to gain knowledge and expertise on birth defects worldwide and to further our domestic goals and those of the international community.
Environmental Public Health Tracking (EPHT)
Environmental public health tracking is the ongoing collection, integration, analysis, interpretation, and dissemination of data on environmental hazards, exposures to those hazards, and health effects that may be related to the exposures.
CDC has worked with representatives from 23 state and local health departments that have received EPHT grants to develop a monitoring system for 12 birth defects. These defects were selected because they are serious birth defects that are relatively easily identified at or around the time of birth, have some potential for environmental risk factors, and could be adequately ascertained by the different types of birth defects tracking systems. The EPHT Network tracks the prevalence of these defects and publishes annual data tables and maps in the national portal. Currently, the national portal has birth defects data for Colorado, Connecticut, Florida, Maine, Massachusetts, Missouri, New Hampshire, New Jersey, New Mexico, New York, Utah, and Wisconsin.
National Birth Defects Prevention Study (NBDPS)
Established in 1997, NBDPS is the largest population-based U.S. study looking at risk factors and potential causes of over 30 major birth defects. CDC funds the study and collects data with researchers from other study sites, collectively called the Centers for Birth Defects Research and Prevention (CBDRP). Participating sites have included Arkansas, California, Georgia (CDC), Iowa, Massachusetts, New Jersey, New York, North Carolina, Texas, and Utah.
Understanding the potential causes of birth defects can help us learn how to prevent them. The NBDPS has made key contributions in understanding the risk of specific medications when used just before and during pregnancy. Data from the NBDPS has also clearly demonstrated that maternal obesity is a strong risk factor for a number of major birth defects and has confirmed the association between maternal smoking and orofacial clefts. The NBDPS is one key step toward bringing us to a day when fewer babies are born with birth defects.
National Health and Nutrition Examination Survey (NHANES)
NHANES is a nationally-representative survey designed to look at the health and nutritional status of adults and children in the United States. The survey is unique in that it combines interviews and physical examinations, including the collection of blood samples.
CDC uses information from these studies to look at the amount of folic acid taken in from food and dietary supplements. Green vegetables, fruits, and juices have natural folate, and other foods, such as cereal and bread, have folic acid added to them. CDC is looking at NHANES data to see how people get folic acid and to see if they are getting the recommended amount. This information will help determine if adding different levels of folic acid to these foods or different types of foods would affect peoples’ intake. CDC is also using these data to look at folic acid intake and blood folate concentrations among women who are pregnant, or who may become pregnant, as well as specifically among women who are obese or who have diabetes. CDC also uses NHANES data to look at patterns of prescription medication use among pregnant women. This information will help determine the most commonly used medications during pregnancy, which CDC will use to identify medications that need future research to characterize their safety or risk during pregnancy.
- Nelson K, Holmes LB. 1989. Malformations due to presumed spontaneous mutations in newborn infants. New England Journal of Medicine 320:19-23.
- Centers for Disease Control and Prevention
National Center on Birth Defects and Developmental Disabilities
Division of Birth Defects and Developmental Disabilities
1600 Clifton Road
Atlanta, GA 30333
TTY: (888) 232-6348
- Contact CDC-INFO