C-Sections Might Put Preemies at Risk for Breathing
THURSDAY, Feb. 9 (HealthDay News) -- Small, premature infants
born by cesarean section are at 30 percent higher risk for serious
breathing problems than those delivered vaginally, a new study
Respiratory distress syndrome, which mostly affects premature
newborns and can lead to ongoing breathing problems, blindness and
brain damage, was more common in the babies born by cesarean, or
C-section, delivery, researchers found.
"I would say that we at least showed that there may not be any benefit to cesarean delivery in preterm births, and more research is needed before the C-section rate goes up even further," said study leader Dr. Erika Werner, an assistant professor of maternal-fetal medicine at the Johns Hopkins School of Medicine in Baltimore.
Between 2002 and 2009, cesarean deliveries in the United States
rose from 27 percent of births to 34 percent, according to a
HealthGrades report. The U.S. Centers for Disease Control and
Prevention recently reported a dip in rates to slightly under 33
percent in 2010.
Groups such as the American Congress of Obstetricians and
Gynecologists are trying to curb cesarean deliveries, but without
"I'm acutely aware as a clinician that the C-section rate is rising, and there were prior studies that really had mixed results," Werner said. "Some suggested an increased risk of bleeding in the brain and some suggested increased risk of death in this population with a vaginal delivery. So I really wanted to look at a contemporary, diverse population."
The researchers analyzed birth data on 2,560
small-for-gestational-age babies delivered between 25 and 34 weeks
of pregnancy in New York City hospitals from 1995 to 2003. (Before
37 weeks is considered preterm). Forty-six percent were delivered
vaginally and 54 percent by C-section. The study only looked at
live births and excluded mothers who had a previous cesarean
Vaginal deliveries that used forceps or vacuum were excluded
from the study, but they're not usually a factor with such small
newborns, Werner explained.
The study found no difference in the incidence of brain bleeds,
seizure or sepsis between the two types of delivery. While
cesarean-delivered babies had lower Apgar scores -- a measure of
newborn health -- the difference was not significant after taking
other factors into account. But the higher risk of respiratory
distress syndrome still held.
The study is slated for presentation Thursday at the annual
meeting of the Society for Maternal-Fetal Medicine in Dallas.
Dr. Diane Ashton, deputy medical director of the March of Dimes,
who was not involved in the new study, said the results echo other
"This particular study shows that for infants that are premature and small-for-gestational-age, which tend to be thought of as rather fragile infants, the cesarean delivery doesn't offer any protection from the adverse outcomes," Ashton said.
In general, the March of Dimes stance "is that elective
deliveries -- and that's cesarean sections and inductions -- should
not occur for infants born before 39 weeks unless there's a medical
indication," she noted.
"For those instances where there is a strong medical indication, either because of the mother's health or the fetus' health, I think it's important that women understand that it's a major surgery and that it can be associated with complications," Ashton added.
Werner said her team did a similar study on premature infants
whose weight fell in the normal range. "We had very similar
outcomes, although the respiratory distress was even more
impressive and there was more of a benefit to vaginal delivery,"
Ashton said that vaginal birth helps babies breathe. "The
process of delivering babies vaginally and going through the birth
canal and getting the amniotic fluid out of the lungs can enhance
their respiratory status," she explained.
While the new study found an association between cesarean
deliveries and breathing problems in preterm babies, it did not
prove a cause-and-effect relationship.
The study relied on birth certificate and hospital-discharge
data. "We don't know if C-section just selects a population more at
risk for respiratory distress or if C-section causes respiratory
distress. We can't tell which comes first in this kind of study,"
Ashton said it's not too soon for these and similar findings to
"Certainly there should be some review and maybe recommendations from the American Congress of Obstetricians and Gynecologists as to where they think practice should change," Ashton said.
Data and conclusions presented at medical meetings should be
viewed as preliminary until published in a peer-reviewed medical
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