Extremely premature baby girls, especially those who are African American, are much more likely to survive than extremely premature white boys, according to research published in the January issue of Pediatrics.
Although the findings are consistent with past research, no one knows exactly what role race and gender play in the survival rates of the premature babies born at the currents limits of survival (less than 28 weeks gestation) with extremely low birthweight (ELBW), said the March of Dimes in commenting on the report.
"We need to understand what gives African-American baby girls a better chance of survival at the earliest extreme of viability. If we can understand the differences in genetic or other influences during gestation between African-American girls and white boys, maybe we can improve outcomes for all premature babies, regardless of their race or gender," said Nancy Green, MD, medical director of the March of Dimes. "That's why the March of Dimes continues to support research on the causes of prematurity."
Additional time in the womb can improve the chances of survival for all premature babies, regardless of race or gender, Dr. Green said. The study in Pediatrics found that for extremely premature infants, as gestational age and birth weight increase, so did the chances of survival.
Some 12.5 percent of all babies -- about 508,000 -- were born prematurely in 2004, according to the latest government statistics. About 1 percent of these babies are considered ELBW.
In this study, 11 percent of babies born at 22 weeks gestation or less survived, compared to 27 percent at 23 weeks gestation. Survival rates reached 85 percent at 28 weeks gestation. Also, about 60 percent of the ELBW babies, those that weighed two pounds or less, survived.
The study also found that extremely premature baby girls were 1.7 times more likely to survive than baby boys. However, African-American baby girls were 2.1 times as likely to survive as white boys. The study only reported on infant mortality. Quality of life or other outcomes, such as complications of the developing brain or lungs, were not assessed.
The study, led by Steven B. Morse, MD, MPH, of the University of Florida, looked at the one-year survival rate of 5,076 ELBW babies born in Florida between 1996 and 2000. "Racial and Gender Differences in the Viability of Extremely Low Birth Weight Infants: A Population-Based Study," appeared in the January issue of Pediatrics, volume 117, number 1.
The March of Dimes is a national voluntary health agency whose mission is to improve the health of babies by preventing birth defects, premature birth and infant mortality. Founded in 1938, the March of Dimes funds programs of research, community services, education, and advocacy to save babies and in 2003 launched a campaign to address the increasing rate of premature birth.