Jan. 7 (Bloomberg) -- Women who chose to give birth by Caesarean section one or two weeks before reaching full-term pregnancy were twice as likely to have babies with complications as those who waited until 39 weeks before having the procedure, a study found.
The research showed twice as many infants delivered by C- section at 37 weeks, or 13 percent, were admitted to the newborn intensive care unit as those born full term at 39 weeks. Four times as many of the younger babies, or 4 percent, had difficulty breathing, according to a report in tomorrow’s New England Journal of Medicine.
The rate of Caesarean births in the U.S. increased to 31.1 percent in 2006, from 20.7 percent of all births in 1996, according to health statistics cited in the study. Nine of 10 women who gave birth that way once have had another Caesarean with subsequent births, according to data from the U.S. Centers for Disease Control and Prevention.
“There are definitely risks associated with delivering early,” said study author Alan Tita, an assistant professor of obstetrics and gynecology at the University of Alabama at Birmingham.
Caesareans may be performed because the mother has health problems, because the baby is badly positioned, or for other health reasons. This study examined only women who chose to have Caesareans, not those who had the surgery out of medical necessity. The study was funded by the U.S. National Institutes of Health.
Although many studies have looked at the risks of Caesarean section compared with vaginal birth, there haven’t been many that considered the timing of the surgery, Tita said. Although the new research looked at repeat Caesarean births, other studies of initial Caesarean deliveries have found similar breathing problems with early procedures.
The researchers examined data from 13,258 Caesarean sections done at 19 medical centers and involving women who had previously had at least one performed and didn’t have any complications in pregnancies. The researchers found 36 percent of the C-sections took place before 39 weeks of gestation.
“The sheer number of infants being delivered early is surprising,” said Amy Murtha, the director of obstetrics research at Duke Medical Center in Durham, North Carolina.
The women who delivered earlier were likelier to be white, married and privately insured. That may be because those women pressure their doctors to schedule their deliveries when it is convenient, said Murtha, who had seen the study.
“These are women who are controlling their schedules,” Murtha said. “Medicaid patients in some ways got better care because they delivered later.”
Advice for Women
The American College of Obstetricians and Gynecologists, a Washington-based women’s health-care association, recommended in in a December 2007 committee opinion that no elective Caesareans be performed before 39 weeks unless there is evidence that the baby’s lungs have developed. That can be determined by amniocentesis, Tita said. This study didn’t examine whether the babies had received testing.
While this study looked at repeat Caesareans, the results probably hold up for women giving birth through Caesarean for the first time as well, Murtha said.
“There’s no reason to think the results of these study don’t apply to first births,” Murtha said.
To contact the reporter on this story: Elizabeth Lopatto in New York at email@example.com.