African American mothers were found to deliver prematurely at 20-34 weeks and more to deliver extremely prematurely at 20-28 weeks. Full term births occur at 37-41 weeks gestation.
The results of the study are published in the February issue of the American Journal of Obstetrics & Gynecology.
African American mothers were also more than 5 times more likely to have repeating premature births than Caucasian mothers. Although all mothers who had initially delivered a premature infant at 20-34 weeks of gestation were more likely to do so again, the rate for Caucasian women was 9.2% and the rate for African American women was 21.5%.
Writing in the article, Louis J. Muglia, MD PhD, from the Center for Preterm Birth Research at Washington University School of Medicine, states, “We find that African-American women experience preterm birth not only at increased rates as compared to Caucasian women, but also at earlier gestations and with increased repetition… [We] further analyze the pattern of recurrent preterm birth stratified by race and find that the tendency to repeat preterm birth during the same week occurs for both Caucasians and African Americans, but the median age for preterm birth is shifted two weeks earlier in African Americans. These findings together highlight the importance of race, particularly after correction for other risk factors, and suggest a probable genetic component that may underlie the public health problem presented by the racial disparity in preterm birth.”