Cesarean Delivery No Safer for Small Gestational Age Infants

Nancy A. Melville

February 10, 2012

February 10, 2012 (Dallas, Texas) — Contrary to widespread belief, cesarean delivery is no safer than vaginal delivery for infants who are premature and small for gestational age, according to research presented here at the Society for Maternal-Fetal Medicine 32nd Annual Meeting.

Clinicians have commonly recommended cesarean delivery for infants who were premature and showed intrauterine growth restriction because it was considered more protective of higher-risk neonates than vaginal delivery.

However, a new study of neonates who were small for gestational age showed that cesarean delivery did not have fewer complications, and in fact had an increased risk for respiratory distress.

"I suspected there might be some benefits to each type of delivery, but it was a surprise to see no benefits...for [cesarean delivery], while there was a benefit for vaginal delivery in terms of less respiratory distress," lead author Erika F. Werner, MD, MS, from the Department of Gynecology and Obstetrics at Johns Hopkins University in Baltimore, Maryland, told Medscape Medical News.

Dr. Werner and her colleagues evaluated data on live singleton births in New York City that were delivered at 25 to 34 weeks of gestation from 1995 to 2003.

Of the 2560 neonates, 46% were vaginal and 54% were cesarean deliveries.

Cesarean delivery did not result in a reduction in the complications that have been perceived as risks with vaginal delivery, Dr. Werner reported. These include intraventricular hemorrhage, subdural hemorrhage, seizures, and sepsis.

"Previous studies have suggested that more intraventricular hemorrhage occurred in babies who were premature and delivered vaginally, particularly those who were very small, weighing less than 750 g," she said.

"There was also some association between vaginal deliveries and increased neonatal death, so people have thought that [cesarean delivery] would protect babies from neonatal death, but this study found that there was not a benefit," Dr. Werner explained.

In fact, the odds of respiratory distress syndrome were 30% higher with cesarean than with vaginal delivery. The rate remained higher after controlling for factors such as the mother's age, ethnicity, education, prepregnancy weight, diabetes, hypertension, and gestational age at delivery.

Infants delivered by cesarean had increased odds of having a 5-minute Apgar score below 7 (odds ratio, 1.4; 95% confidence interval, 1.1 to 1.9). No difference was seen after adjustment for confounding factors.

In addition to respiratory distress, cesarean delivery is associated with another well-known consequence — the increased likelihood of future cesarean deliveries, Dr. Werner noted.

"Clinicians should consider that in not trying for that first vaginal delivery, they're sort of encouraging future [cesarean deliveries]," Dr. Werner cautioned.

This study received recognition from the March of Dimes for representing innovative research that focuses on preventing premature birth and related complications.

According to Diane Ashton, MD, MPH, deputy medical director of the March of Dimes, the findings underscore the recommendation of the American College of Obstetricians and Gynecologists (ACOG) that infants who are preterm don't benefit from cesarean deliveries.

"The same is true for preterm infants who are small for gestational age, meaning less than the tenth percentile in weight," she told Medscape Medical News.

"These infants are doubly stressed. In addition to being preterm, there is something else going on that is stunting their ability to grow normally. This study shows that they do better with vaginal delivery than [with cesarean delivery]."

More than half of the preterm, small for gestational age infants were delivered by cesarean in this study, despite the ACOG recommendation. This highlights a persisting tendency by clinicians to opt for cesarean delivery with these higher-risk infants, erring on what they believe is the side of caution," she noted.

"One of the difficulties in studying this particular situation with preterm, small for gestational age infants is that the numbers tend to be very small and it's hard to get a critical mass of infants that fall within that criteria to come to a good conclusion."

"But apparently, that's what the authors of this study were able to accomplish. It's just a matter of making sure that the information is widely known," Dr. Ashton said.

The authors and Dr. Ashton have disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 32nd Annual Meeting: Abstract 13. Presented February 9, 2012.

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