Doctors have long assumed that Cesarean sections might be the best choice for babies that will be born preterm.
But a new study shows that C-sections are no safer than vaginal delivery for the most fragile of infants, those who are born early and who are small for their age. In fact, C-sections might actually lead to a greater risk of respiratory problems and other complications in these infants, according to a report presented at the annual meeting of the Society for Maternal-Fetal Medicine.
The new results suggest that doctors need to re-think how they look at C-sections, said the study’s lead author Dr. Erika Werner, an assistant professor of gynecology and obstetrics at the Johns Hopkins School of Medicine.
“You shouldn’t assume there’s no downside to the baby with a C-section,” Werner said.
This kind of information becomes increasingly important as Cesarean deliveries become more and more common. The Centers for Disease Control and Prevention found that C-section rates rose 33 percent from 2000 to 2007, with women under the age of 25 experiencing the greatest increase at 57 percent.
“The rates of C-section are going up in this country,” said Dr. Nancy Snyderman, NBC’s chief medical editor. “One reason may be in vitro fertilization and multiple births. One part of it, though is women trying to put delivery on their own schedules. And, you’ve heard this before: ‘too posh to push.’”
The most recent data – from 2009 – show that 45.6 percent of premature babies were delivered by Cesarean section, as compared to 35.1 percent of those born at 37-38 weeks.
Part of the explanation for the especially high rate among preemies may lie in the assumption that vaginal births might be too traumatic – and dangerous - for fragile infants who are underweight and preterm, said Dr. Diane Ashton, deputy director at the national office of the March of Dimes.
“When I was in my obstetric residency training in the late '80s, we were taught that it would be protective to do Cesarean deliveries on preterm babies because vaginal birth might put them at risk for internal hemorrhages and other complications,” Ashton said.
The push for C-sections was especially strong when it came to infants who weren’t growing fast enough in the uterus, Snyderman told TODAY’S Ann Curry Thursday. “The conventional wisdom has been to get those babies out and we’ll treat them in an ICU,” Snyderman said.
For the new study, Werner and her colleagues scrutinized the medical records of 2,560 babies born preterm between 1995 and 2003 in New York City. More than half -- 54 percent -- of the babies had been delivered through Cesarean section
Babies born vaginally were no more likely to have developed subdural hemorrhages, seizures, or sepsis than those delivered by C-section. Instead, the researchers found that babies born by C-section were 30 percent more likely to develop respiratory distress syndrome. And this may have long term fallout for the babies, Snyderman said.
“The breathing problems can turn into asthma later in life,” she explained. “In the last few weeks of pregnancy, that’s when the lungs and the brain are developing. So developmental problems, cerebral palsy, learning disability – all those things become compounded if a baby is taken out prematurely.”
One thing the researchers don’t know is why doctors chose to deliver the babies in the study via C-section. It’s possible, Werner allowed, that in some cases C-sections were chosen to speed delivery because the baby’s or the mother’s lives were at risk.
But in cases where there is no imminent danger to the baby or the mom, doctors should lean towards vaginal delivery, both Werner and Ashton said.
And that’s probably true for full-term babies too, Werner said.
“I think there’s a chance that full term infants might also have lower rates of respiratory distress,” Werner said. “That’s speculation at this point. But it’s another reason for doctors to think a lot about the benefits of vaginal delivery.”
“When you start to look at 37 maybe 38 weeks, there’s an increased belief now that the longer a baby stays in the womb, up to 40 weeks, the better the outcome is for the baby,” she said.There are women who want a C-section to avoid labor pain, Snyderman said.
”They say ‘I don’t want the pain, please let me just do a C-section,’” she added. “You have to remember the ultimate outcome should be a healthy baby.”