Pregnant women who avoid drugs and rock and roll may still be at risk for delivering premature babies, according to a study that found black mothers are three times as likely to give birth three to 17 weeks early when compared to white mothers.
Prematurity is on the rise, with the March of Dimes reporting that one in eight babies is born before the full 38-week gestation period. In the past decade, studies all over the country have been finding correlations between genetic makeup and preterm births.
With permission from the Missouri Department of Health and Senior Services, researchers at the Washington University School of Medicine retrospectively analyzed over 368,600 birth records dating from 1989 to 1997. Professor of Pediatrics Louis Muglia and his team sifted through records indicating the status of birth mothers, including maternal age, health, race, socioeconomic status and education level. The study accounted for these variables by using logistic regression graphs.
“We found that there are many factors that increase the risk of preterm delivery in women,” Muglia said. “But even if you adjust for all those other factors,” black women have about a 3 percent greater risk of delivering prematurely between 20 and 34 weeks.
Compared to white mothers, black women had a nearly 4 percent higher risk of delivering prematurely between 20 and 28 weeks of gestation, a period that just clears the age of viability, meaning that the baby will be able to survive in the outside world.
Of the approximately 368,800 births, 17 percent were born to black women and 81 percent were born to white women. The other two percent were of other racial groups. Twins and multiple births, which are usually born prematurely, were excluded from the study, which was published in February’s American Journal of Obstetrics and Gynecology.
Other studies also suggest that gestation period may be influenced by genetic factors. A 1998 study published in the Oxford University Press found that Swedish women whose older sisters had given birth to preterm babies had an 80 percent increased risk of delivering a premature child.
A more recent study from Virginia Commonwealth University reported last year that compared to women of European descent, black women have a twofold risk for having a gene variation that causes a woman’s water to break prematurely.
Associate Professor of Psychology, Jan Duchek found Muglia’s study intriguing because it reported that for both whites and blacks, more than 50 percent of recurrent preterm births occur within the same two to three week period of the first preterm infant. Of the group with successive preterm births, black mothers were two to three times more likely to give birth prematurely.
“When you hear things about the subsequent birth, and the similarity of when the premature birth occurs for a particular woman, it really does make one seriously think about racial and genetic factors,” said Duchek.
F. Sessions Cole, director of the Division of Pediatric Newborn Medicine and chief medical officer at St. Louis Children’s Hospital, is one of the seven other researchers who helped Muglia conduct the study.
Cole emphasized that preterm babies face many health problems. Because the lungs develop in later gestation, many premature infants need breathing ventilators and may acquire asthma later in life. Preterm babies may also have brain developmental problems, hearing difficulties and visual problems following birth.
Preterm infants will often stay in the hospital for their remaining time of the 38-week gestation period. Medical care can cost up to $2,500 to $3,000 a day.
“If you asked the question, how much does the technology cost per year that it saves, actually this is one of the cheapest technologies in medicine,” Cole said. “When our babies do well, they do well for 70 years.”
Muglia’s study is part of a larger effort sponsored by the March of Dimes to identify the genes involved in preterm birth. He hopes to one day understand the genetic processes determining gestational periods.
“Hopefully the study will pave the way, not only to motivate black women to seek medical input both prior to conception and early in pregnancy to try to reduce their risk of preterm birth, but also motivate scientific efforts to identify those specific genes pathways of genes that account for this increased risk,” said Cole.