Episiotomies do not prevent shoulder injury to infants stuck in birth canal

A new study from Johns Hopkins suggests that routine widening of the vagina, a procedure known as an episiotomy, does not reduce the risk of injury to infants during a complicated birth, such as when a baby’s shoulders are stuck in the birth canal after the head is already out. Instead, physicians can proceed directly to physical maneuvering of the infant, thereby avoiding unnecessary trauma to the mother and, at the same time, averting injury to the baby. An episiotomy should only be performed when more room is required to carry out maneuvers to dislodge an infant.

“Most textbooks in obstetrics still recommend that physicians perform a generous episiotomy, yet there is no evidence that the procedure will reduce the likelihood of injury to the infant,” said high-risk obstetrician Edith Gurewitsch, M.D., an assistant professor at The Johns Hopkins University School of Medicine and lead author of the study, presented at the 24th annual meeting of the Society for Maternal-Fetal Medicine and set for publication in the American Journal of Obstetrics and Gynecology online Oct. 5.

“Episiotomy will only eliminate soft tissue barriers to delivery, whereas rotating the infant will realign its shoulders to fit within the mother’s pelvis. It is the bony pelvis that is widely acknowledged as the main cause for the infant getting caught in the birth canal.”

During an episiotomy, a physician will make a small surgical cut between a mother’s vagina and rectum in order to widen the opening for delivery. This incision does not usually penetrate the rectum, but there is a risk that the cut will extend this far when an episiotomy is performed. After birth, the incision wound is sewn up, and it usually takes four to six weeks for recovery.

When an infant’s shoulders get stuck at the last moment of delivery, a condition called shoulder dystocia, there is an urgent need to finish delivery within six to eight minutes in order to reduce the risk of brain damage or death by suffocation. A more common complication is a shoulder injury to the infant as a result of attempts to dislodge the baby from the birth canal. In response to shoulder dystocia, physicians must take extra steps beyond pulling on the head to dislodge the infant. Traditionally, these options have included procedures to widen the vagina or physically rotate the baby.

As part of the study, the Hopkins team retrieved medical records from three large databases and found 592 cases where there was difficulty delivering the baby’s shoulders. Their aim was to determine which method used to finish delivery – episiotomy, or physical maneuvering of the infant in the birth canal, or a combination of both – is most effective at reducing the number of shoulder injuries, a condition called brachial plexus palsy.

A detailed analysis of the most severe cases of shoulder dystocia, a total of 127 records, showed that the rate of brachial plexus palsy did not differ among deliveries managed by just rotating the infant and deliveries managed by a combination of physical maneuvers and episiotomy, 58 percent and 60 percent respectively. When infants were maneuvered during deliveries without an episiotomy, half the women came away with their vaginas intact and there were fewer shoulder injuries among the infants, 35 percent.

“An episiotomy is a surgical procedure that that should only be performed when it is absolutely necessary,” said Gurewitsch. “We now know that it does not help prevent brachial plexus palsy in the infant during shoulder dystocia, whereas the procedure may cause harm to the mother through unnecessary trauma from surgery. Indeed, the procedure puts the mother at increased risk of postsurgical infection, bleeding and pelvic floor disorders, such as long-term discomfort during intercourse, flatulence and possible incontinence.”