"Very small babies delivered prematurely by Caesarean section because they were not growing properly in the womb developed more respiratory problems than those who had induced vaginal deliveries, a new study found. The study adds to growing concern over the high rate of Caesarean section deliveries in the United States, which reached 32 percent, or nearly one in three deliveries, in 2007.
On Wednesday, the federal secretary of health and human services, Kathleen Sebelius, announced a public health campaign to educate families that it is best for both the mother and the baby to let a problem-free pregnancy go for as long as possible, and to let labor start naturally. The campaign is a partnership that expands on a March of Dimes public awareness drive emphasizing that “healthy babies are worth the wait.”
The latest study looked at babies who were extremely small for their gestational age and not growing properly in utero, so waiting was not a medical option. But the findings raise new questions about the risks of Caesarean section.
For the study, researchers analyzed nine years of data from births in New York City, identifying 2,560 babies who were small for their gestational age and delivered between 25 and 34 weeks of pregnancy. Forty-six percent were delivered vaginally, and 54 percent by Caesarean section.
“The conventional thinking, though nobody really knew, was that maybe it would be less traumatic for this group to have a C-section, and they might benefit,” said Dr. Erika F. Werner, an assistant professor at Johns Hopkins School of Medicine and the study’s lead author. “Our study suggests that may not be true.”
In fact, the babies delivered by C-section were 30 percent more likely to develop respiratory distress syndrome, a serious breathing disorder that can lead to organ damage and that is more common in premature infants, Dr. Werner and colleagues from Brown and Yale Universities found.
The C-section deliveries were not associated with improved outcomes in terms of other complications, including hemorrhages, seizures, low Apgar scores and sepsis, the researchers found. Results were adjusted for differences in the mother’s age, ethnicity, education, health status and weight.
The findings are being presented today at the annual meeting of the Society for Maternal-Fetal Medicine in Dallas.
“The takeaway is that if you’re in this situation, you should have a frank discussion with your doctor that maybe a vaginal delivery is equivalent, or even better,” Dr. Werner said. “We need further research to determine if there is any benefit to C-section” for such infants, she said.
Another consideration is that when a woman has one baby born by Caesarean section, subsequent children are far more likely to be delivered by C-section as well.
As to why vaginal deliveries appear to improve respiratory function, Dr. Werner said, “We don’t have the perfect answer.” Some experts believe that the physical compression the baby experiences during labor helps remove fluid from the lungs and prepares the baby to breathe air.
Dr. Diane M. Ashton, deputy medical director of the March of Dimes, who has been overseeing the organization’s Prematurity Campaign to educate the public, said similarly improved outcomes are seen with infants delivered further along in a pregnancy.
“This is consistent with what is seen in infants even at 37 weeks,” she said. “They, too, have better respiratory outcomes when delivered vaginally versus C-delivery.”
Studies suggest that premature births of single babies have been increasing in recent years and that more are being delivered by Caesarean section, including C-sections that are not medically necessary. At the same time, recent research shows that a baby’s lungs and brain undergo important growth and development during the last few weeks of pregnancy, and that babies born just three to six weeks before their due dates are more likely to suffer disabilities or developmental delays in kindergarten.
Last year, the American College of Obstetricians and Gynecologists issued new medical guidelines meant to lower the rate of repeat Caesareans by making it easier for women to find doctors and hospitals that will let them attempt a vaginal delivery even when a previous baby was delivered by C-section. Although these women are at risk for a serious complication called uterine rupture, ruptures affect fewer than 1 percent of women, while C-sections, which involve major abdominal surgery, carry many other risks both to the mother and to the child."
C-Sections Pose Respiratory Risks for Some Small Preemies