As cesarean section rates continue to climb in the United States, researchers are looking to understand the factors that might contribute. There has been debate in the field about whether non-medically required induction of labor leads to a greater likelihood of C-section, with some studies showing an association and others demonstrating that inductions at full term can actually protect both the mothers and babies. In order to tease apart the evidence, a new analysis pooled the results from five randomized controlled trials including 844 women, and found no link between induction and rates of C section in uncomplicated pregnancies of singleton babies at full term. The results were published online April 13th in the American Journal of Obstetrics & Gynecology.
"Although babies have been delivered for centuries, we are still researching the best and safest methods for the mother and baby," says Vincenzo Berghella, M.D., Director of Maternal Fetal Medicine and a Professor of Obstetrics and Gynecology at Thomas Jefferson University. "Obstetrics today offers women many more options for pain relief and safe delivery, but we have not studied with proper randomized trials which methods are most appropriate for which situations, and what gestational age is best for mother and baby." In the current analysis Dr. Berghella together with co-author Gabriele Saccone, M.D., at the School of Medicine at the University of Naples Federico, in Italy, combined data from studies that looked at women who delivered between 39 and 40 weeks and 6/7 days, whose water didn't break prior to onset of labor, in order to capture only those women whose inductions were without medical indication, rather than medically necessary.
The researchers did not find any increase in risk of C-section in women who were inducted at 39 0/7 weeks versus those that weren't until at least past 40 0/7 weeks. Instead, the researchers noted several benefits of induction at 39weeks. First, induction was associated with slightly less blood loss than non-induced birth (a volume of about 50ml). Second, meconium staining, a potentially serious complication, was also less likely to occur in babies of induced mothers. Research has established that women who give birth much past their due date (40weeks) are more likely to have meconium in the amniotic sac. Meconium is an unborn baby's fecal matter, which can be excreted into the sac. When this occurs there is an increased risk of infection for the mother and the baby, and a chance that the baby will inhale the matter into his or her lungs, which in some cases can lead to death.
Finally, as expected, the study found that birth weight was lower in babies of inducted mothers, but only by 136 grams (about 5 ounces).
"Some experts in our field are calling for induction at full term to become the standard of care," says Dr. Berghella . "While I don't think this review will change standards of care, it clearly shows that there are some minor benefits (with induction at 39weeks even without medical indications) that obstetricians may want to consider." However, says Berghella, final word on this topic will have to wait until the results of an ongoing multi-centered clinical trial from the NIH is published (NCT01990612).
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