Progress Made in Estimating Frequency of Birth Defects: New Numbers Provide Improved National Estimates for 18 Birth Defects
Among the 18 major birth defects studied, orofacial clefts (cleft lip and cleft palate) were the most common birth defect in the United States, affecting an estimated 6,800 infants annually, according to the Centers for Disease Control and Prevention (CDC) estimates released in its journal Morbidity and Mortality Weekly Report (MMWR). Major birth defects are conditions that are present at birth and have a serious, adverse impact on health, development or functional ability.
The condition with the second highest prevalence was Down syndrome, which affects about 5,500 infants a year. Among the 18 major birth defects selected for this study, each of 10 different types of birth defects affected more than 1,000 babies per year.
“Birth defects are a leading cause of death in the first year of life,” said José Cordero, director of CDC’s National Center on Birth Defects and Developmental Disabilities. “With more accurate estimates of how often and where birth defects are occurring, we hope to learn more about how we can prevent them. With improved information, we can better plan for and address the health and education needs of children with birth defects.”
Although federal, state and local surveillance data suggest that approximately 3 percent of babies born in the United States are affected by a major birth defect of some type, this is the first effort to develop population-based national prevalence estimates for these 18 specific birth defects.
The data used to develop the national estimates came from 1999-2001 National Birth Defects Prevention Network (NBDPN) information for 11 states: Alabama, Arkansas, California, Georgia, Hawaii, Iowa, Massachusetts, North Carolina, Oklahoma, Texas and Utah. These states are the only ones that send staff to hospitals to review records and identify babies with the 18 major birth defects for which the national prevalence was estimated.
CDC used the pooled state-level data and applied it to the U.S. population overall after adjusting for race/ethnicity or the age of the mother. The report represents important progress toward estimating national prevalence for 18 major birth defects using population-based data. The population-based national estimates are important to help plan for children’s health care and educational needs, and to help determine resource needs for basic and public heath research.
For example, national prevalence estimates were previously made for neural tube defects including spina bifida (failure of the spine to close properly during fetal development resulting in significant damage to the nerves and spinal cord) and anencephaly (failure of the top of the neural tube to close properly resulting in absence of a major portion of the brain and skull) to assess the impact of folic acid fortification. These efforts found that neural tube defects declined 26 percent following folic acid fortification of the U.S. cereal and grain supply.
The National Birth Defects Prevention Network collects data from 34 participating states on up to 45 major birth defects. The CDC assisted in the development of the NBDPN and supports the organization’s surveillance activities. The network’s efforts to standardize and improve methods for identifying birth defects and tracking surveillance have facilitated important projects such as the estimates published today. The support of the March of Dimes has also been critical in this effort.
January is Birth Defects Prevention Month, designed to highlight steps women can take to help achieve a healthy birth. In addition, January 9-16 is Folic Acid Awareness Week, highlighting the importance of folic acid – a B-vitamin – in preventing neural tube defects.
For more information please visit www.cdc.gov/ncbddd/bd/abc.htm.