Cesarean sections may not be best for preterm babies who are small for their gestational age, a new study found. It suggests than those infants have no better outcomes than babies born vaginally and may, in fact, have higher rates of serious respiratory problems.
In the new study, presented Thursday at the Annual Society for Maternal-Fetal Medicine meeting, researchers reviewed birth certificates and hospital discharge data for more than 2,500 babies born in New York City. The babies were preterm and also weighed substantially less than babies typically do at that stage of development. Some 46 percent were delivered vaginally, while 54 percent were delivered by C-section.
There were no significant differences in either group of babies developing the health issues that can sometimes result from preterm birth, such as bleeding inside the brain, seizure or potentially life-threatening infections.
However, C-sections were associated with an increased risk of respiratory distress syndrome, which occurs in newborns whose lungs are not fully developed.
"The fact is, about 54 percent of the babies these researchers looked at had Cesarean deliveries, so it is a fairly common practice still," said Dr. Diane Ashton, deputy medical director at the March of Dimes. The nonprofit, which provides information and support to women for healthy pregnancies, was not responsible for the study but is praising it -- saying in a press release that the research helps fight the "widely-held assumption" that C-sections have no health risks for babies.
An abstract for the presentation does not delve into why small preemies born via C-section may be at greater risk for lung problems, but Ashton explained that when a fetus passes through the vaginal canal during natural delivery, the chest area is compressed, forcing out amniotic fluid so the lungs are not particularly wet when the baby emerges. In a C-section, that does not happen.
Overall, Ashton said the study emphasizes that small, preterm babies who have no other health complications that would require a C-section should be delivered vaginally.
"The importance of this article is that [in these cases], vaginal delivery is a better outcome," she told HuffPost. "Cesarean delivery does not improve the risk of many of the complications these babies can have."
But in spite of mounting evidence of the benefits of natural delivery when possible, C-sections continue to be common in the U.S.
According to the Centers for Disease Control, 32 percent of all births in the U.S. in 2009 -- the last year for which data is available -- were Cesarean deliveries. In the last several decades, preterm births have increased by more than 30 percent in the U.S., although the rate recently declined for the third straight year -- to 12.8 percent of all births.
"We don't do sections capriciously, though, and there are a lot of reasons why section rates are so much higher for preemies," said Dr. Virginia Lupo, an OB-GYN with the Hennepin County Medical Center in Minnesota. "They much more often have abnormal presentations (breech or sideways) since they are still so small relative to the large amount of fluid in the uterus, and a lot of times preemies are being delivered for a reason -- bad high blood pressure, or diabetes or some other medical problem that requires that they be delivered pronto, when you can't wait for a 24-hour labor to start and then progress."
The takeaway from the current research, she said, is that if women find themselves in a situation where a doctor is offering a C-section delivery for a small, preterm baby that has no other complications, they may want to lean towards the regular delivery.
"Vaginal delivery has some real advantages over Cesarean delivery," she said.