By Rob Stein
Washington Post Staff Writer
Thursday, January 8, 2009
The common practice of scheduling a Caesarean section a little early to make childbirth more convenient sharply increases the risk that babies will be born with potentially serious complications, according to the first large-scale study to examine the dangers.
The study of more than 24,000 full-term infants found that those delivered at 37 weeks to mothers who had elective repeat C-sections were about twice as likely as newborns delivered at the recommended 39 weeks to experience breathing problems, bloodstream infections and other complications. Babies born at 38 weeks were 50 percent more likely to have problems; the risk was about 20 percent higher just a few days early.
"Having a baby at term, you might expect the baby would do well and come to your room with you and then go right home with you," said Catherine Y. Spong of the National Institute of Child Health and Human Development, which sponsored the study in today's issue of the New England Journal of Medicine. "This shows there are significant risks."
The findings come as health authorities have become increasingly alarmed about the rate of Caesarean births, which has been rising steadily and is now at an all time-high, according to another federal report released yesterday. More than a third of U.S.-born babies are delivered by C-section, which involves removing the baby through a surgical incision in the abdomen instead of vaginally through labor.
The reason for the increase has been the subject of intense debate. In part it is the result of more women having children later in life, when complications are more common. In part it is because doctors are identifying more problem pregnancies early and intervening to protect the mother or the baby. And once a woman has had a C-section, she is much more likely to deliver subsequent children the same way.
Although a pregnancy is considered full term after 37 weeks, the American College of Obstetricians and Gynecologists recommends that elective repeat C-sections occur no earlier than 39 weeks to make sure the baby has fully developed. But some women opt to deliver a little earlier for a variety of reasons, including being eager to see their baby, being tired of pregnancy or for convenience.
"Sometimes a patient is bonded to their physician and that physician may be going out of town and the patient wants that physician to perform the delivery and says, 'Can we schedule it when you're in town?' " Spong said. "Sometimes her in-laws are coming at a certain time and she may want to deliver then."
Although previous studies have suggested increased risks in C-sections before 39 weeks, the new study is the first large-scale attempt to confirm and quantify those risks.
"I think that as a patient or a physician, you might be convinced that being close to 39 weeks is probably good enough and there's probably no difference if you are going to turn 39 weeks on a Sunday to have a Caesarean on, say, a Friday," Spong said. "Before this, we didn't have the data to say that there would be more risk."
For the study, Alan T.N. Tita of the University of Alabama at Birmingham and his colleagues analyzed data collected by the National Institute of Child Health and Human Development, which gathers data on pregnancies at 19 medical centers nationwide.
Of 24,077 women who gave birth through a repeat C-section between 1999 and 2002, 13,258 were clearly elective -- meaning the researchers could find no evidence that the baby or mother was in distress or any other medical reason the woman could not attempt to deliver through labor. Of those, nearly 36 percent of the deliveries occurred before 39 weeks.
"To have more than a third of them done before 39 weeks is surprising," Spong said. "These are all elective repeat Caesareans without a medical indication and without labor."
Because the study was conducted at academic medical centers that are most likely to follow official recommendations, the actual rate may even be higher, Tita said.
More than 15 percent of the babies delivered at 37 weeks suffered a complication, such as problems breathing, low blood sugar, infections or conditions that required intensive care, compared with about 8 percent of those delivered at 39 weeks. About 11 percent of those delivered at 38 weeks experienced complications. Babies born at 37 weeks were four times as likely as those delivered at 39 weeks to have breathing problems.
Although most babies with these complications recover quickly, they can need testing and treatment, including intensive care, that require them to remain in the hospital for at least several days. In some cases, the complications can be dangerous.
"Respiratory distress requiring a ventilator can be life-threatening," Spong said. "So although most do well, there is the possibility of serious adverse outcomes."
At the very least, such complications are stressful for parents and their babies.
"There are economic implications and emotional and impact on the families," Spong said. "Breast-feeding is more difficult, and bonding is more difficult."
While other experts agreed that the study provides important information to help women and their doctors make decisions about timing C-sections, some said the risks of complications are relatively low and need to be weighed against the small but not insignificant chance that waiting a week or two would result in more stillbirths.
"This paper, although it provides important information about risk, does not give us the whole story," said Michael F. Greene of Massachusetts General Hospital in Boston, who wrote an editorial accompanying the study. "It doesn't provide an accounting of how many babies may have died waiting to get to 39 weeks. You have to balance both sides of the ledger."
But Spong said the magnitude of the risk of stillbirth from waiting is unclear, and the new study shows the risks of complications from early delivery is significant.
"It's hard to advocate doing a Caesarean at 37 weeks to try to prevent a stillbirth when we don't really know the true risk," she said.