Birth Defects Research 

• Key findings from Recent Branch Research Projects

• The National Birth Defects Prevention Study

• State Services

• Scientific Publications (by author)

• International Research

To prevent birth defects, we need to learn more about their causes. If we can identify exposures or other factors that may cause or increase the risk of a baby having a birth defect, we can provide that information to women who are planning a pregnancy or who are already pregnant. For example, the prescription acne medication Accutane^® can cause severe birth defects if used during pregnancy. Since Accutane^® is known to cause birth defects, the package carries clear warnings advising women of the danger, and reproductive-age women are asked to enroll in the Boston University Accutane Survey. Accutane^®-exposed pregnancies continue to occur, and CDC recently conducted a field investigation of women with recent Accutane^®-exposed pregnancies to learn more about why these pregnancies occur and what steps could be taken to prevent such exposures.

Research can also identify factors that may prevent or reduce the risk of a baby having a birth defect. Numerous studies have demonstrated that women who take a daily multivitamin containing folic acid before becoming pregnant and in the early weeks of pregnancy have a lower risk of having a baby with a neural tube defect, such as spina bifida or anencephaly, than women who do not take multivitamins during this period. A recent community-based intervention in China demonstrated that the use of folic acid alone can dramatically reduce the risk of neural tube defects in populations with higher and lower prevalence of neural tube defects.

Although 1 in 33 babies in the U.S. has a birth defect, there are many different types of birth defects and each individual defect is rare. For example, hypoplastic left heart syndrome affects about 3 of every 10,000 babies, and cleft lip with or without cleft palate affects about 1 of every 1,000 babies. It is necessary to study each defect separately to learn more about the causes of birth defects because different factors may cause each type of defect. In order to complete this important research as quickly as possible, collaboration between multiple research sites is essential. CDC has established Centers for Birth Defects Research and Prevention in Arkansas, California, Iowa, Massachusetts, New Jersey, New York, and Texas. These seven centers and the eighth site at the CDC (Atlanta, Georgia) participate in the National Birth Defects Prevention Study (NBDPS). The NBDPS is one of the largest studies ever conducted on the causes of birth defects. Information is collected about "cases" who have a major birth defect and "controls" which are infants with no birth defects. The mothers of both "case" and "control" infants complete an extensive telephone interview about their pregnancy and medical history, occupational and environmental exposures, lifestyle, diet, and medication use. NBDPS will also study genetic factors using cheek cells obtained by gently rubbing a brush on the inside of the cheek. Analysis of the data from this study will provide important information about the environmental and genetic factors that contribute to birth defects.

[For more information, click here to see the PDF file.]

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State Services

In 1996, Congress directed CDC to establish Centers of Excellence for Birth Defects Prevention Research.  In 1996, we gave the first cooperative agreement awards of $500,000 per year for 5 years to organizations in California and Iowa.  We have since increased the awards to $800,000 per year and granted similar cooperative agreement awards to organizations in Arkansas, Massachusetts, New Jersey, New York, and Texas.  The centers established in these states will expand and improve existing surveillance, for example, by integrating prenatal diagnoses into surveillance activities.  They will also develop, implement, and evaluate local studies in the following categories: the effectiveness of various methods for the primary prevention of birth defects, the teratogenicity  of various drugs, the environmental causes of birth defects, and the genetic factors that make people susceptible to environmental causes of birth defects, the behavioral causes of birth defects, and the costs of birth defects.

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National Birth Defects Prevention Study.  The largest activity for the seven
centers will be their participation in the National Birth Defects Prevention Study, a case-control study of infants born with major congenital anomalies. The study involves an interview with the mother of study infants and the collection of biological specimens (via cheek swabs) from the infants and their mothers and fathers. Each center will enroll at least 300 case and 100 control infants each year, making this study the largest case-control study of birth defects ever undertaken. Our Birth Defects and Pediatric Genetics Branch, which has been conducting a similar risk-factor study since 1993, will also participate. CDC will pool the data and make them available to all collaborating researchers.

[For more information, click here to see the PDF file.]

Chinese study of the effectiveness of folic acid in a community intervention.  During 1998, we finished analyzing the data from a study conducted jointly with Chinese health officials to determine folic acid’s effectiveness in reducing rates of neural tube defects (NTDs) in two areas of China.  In summary, this study showed that in northern China, which has a high incidence of NTDs, women who took 400 micrograms (0.4mg) of folic acid daily at least 80% of the time before and in the early stages of pregnancy reduced their risk of having an NTD-affected pregnancy by 85%.    Among participating women in southern China, where the incidence was lower (similar to the U.S. NTD rate), the reduction in risk was 40%.