THURSDAY, Sept. 23 (HealthDay News) -- Congenital heart defects -- abnormalities present at birth -- contribute to racial differences in rates of newborn deaths in the United States, according to a study released Thursday.

Researchers at the U.S. Centers for Disease Control and Prevention analyzed data on 11,383,665 live births in the United States between 2003 and 2006, and found that a congenital heart defect was the underlying cause of death in 4.2 percent (2,256) of the 54,008 neonatal (first month of life) deaths among white and black infants.

Those deaths included 1,777 (5.4 percent) of 33,205 infants of white mothers and 479 (2.3 percent) of 20,803 infants born to black mothers, according to the report published Sept. 24 in the CDC's journal, the Morbidity and Mortality Weekly Report.

The study authors also found that a congenital heart defect was the underlying cause of death in 24.5 percent of neonatal deaths attributed to birth defects.

Deaths from congenital heart defects were 30 percent lower among premature infants born to black women (4.5 per 10,000 live births) than among premature infants born to white women (6.8 per 10,000).

But full-term infants born to white women were less likely to die because of a congenital heart defect (1.3 per 10,000) than those born to black women (1.5 per 10,000), a 20 percent difference, the study noted.

The reasons for these racial/gestational age differences in neonatal deaths caused by congenital heart defects aren't clear, the researchers noted.

The CDC researchers concluded that further investigation should include an examination of different factors that affect diagnosis of congenital heart defect during pregnancy and a look at differences in the accuracy and completeness of cause of death reporting by race/ethnicity.

More information

The March of Dimes has more about congenital heart defects.