Early in the last century, obstetricians began to make a routine cut just outside the delivering mother's birth canal to ease the baby's entry to the outside world and prevent painful tearing of the woman's tissue.
The idea seemed so logical that, by mid-century, some hospitals were performing episiotomies in the majority of deliveries. The trouble was, there was no evidence that its routine use was beneficial.
Old habits die hard, but this one may finally be on the wane.
Today, the American College of Obstetricians and Gynecologists is urging doctors to spare the knife unless there is a clear medical reason to intervene. Study after study, the group says, show that routine episiotomies can lead to more serious tears than the infant would cause by a natural exit.
And there is no evidence, according to the standard-setting organization, that women have less pain, better sexual function and less risk of bowel and bladder incontinence when the incision is made as a matter of routine.
"It took an accumulation of data to say that none of our hopes for this procedure were being realized," said Dr. Katherine Hartmann, director of the University of North Carolina's Center for Women's Health Research.
Last year, Hartmann was the lead author of a literature review in the Journal of the American Medical Association that pulled together data from seven previous studies on routine episiotomies involving 5,001 participants. Her article helped inform the ACOG committee that today is releasing a practice bulletin to the nation's obstetricians.
Episiotomy rates vary greatly across the country, with doctors performing the procedure in a third of all vaginal deliveries in 2000, according to ACOG.
Hartmann said her review showed that a third of women will not have a tear requiring sutures if they are left alone. "So every time you perform a routine episiotomy, you deprive 33 percent of women the opportunity to have a lesser injury or no injury," she said.
The remaining women will have tears that require stitches, but most are less severe than the ones that can occur when the baby's head stretches and tears a doctor's incision.
"When you start with an episiotomy, it's easier for that tear to extend," Hartmann said. "A spontaneous tear sounds awful, but it happens along more natural tissue plains."
Hartmann's article, along with today's practice bulletin, confirms what many doctors were beginning to conclude. Though more than 700,000 episiotomies were performed in 2003, according to the bulletin, that was fewer than half the number performed a decade earlier.
"I have not done routine episiotomies since leaving my residency about 19 years ago," said Dr. Steven J. Adashek, an obstetrician at St. Joseph Medical Center in Towson. "There is a place for them, but I'd say only 5 to 10 percent of my deliveries end up with episiotomies."
Adashek said that when he trained at the University of Maryland Medical Center, he learned that the natural rocking of the baby's head as it descends helps to stretch the mother's tissue and prevent serious tears. Doctors and nurses can also help stretch the tissue through massage.
"If the vaginal opening is of adequate size and the baby is not too big, then no episiotomies need to be done," Adashek said. He said he usually makes the call as the baby's head starts to emerge.
"If in my opinion, it's going to tear across the bottom, then an episiotomy should be done."
Dr. Hugh E. Mighty, director of obstetrics and gynecology at the University of Maryland School of Medicine, said he endorses the watch-and-wait strategy.
"These are really judgment calls," he said. "What you're trying to decide is those cases where an episiotomy may be indicated. You're waiting for it to occur."
Doctors sometimes perform an episiotomy to prevent the infant's shoulders from becoming stuck in the birth canal once the head is already out, a condition known as shoulder dystocia. When this happens, doctors are under pressure to deliver the baby within several minutes to prevent brain damage, suffocation or a shoulder injury.
But Hartmann found only one study that examined the role of episiotomies in preventing dystocia, and it found no evidence that the procedure reduced the risk. Today's bulletin, however, says doctors might find episiotomies to be helpful in managing the condition once it occurs.
Two years ago, doctors at the Johns Hopkins School of Medicine concluded in a study that doctors can usually coax the baby out of the birth canal without an episiotomy. Among their techniques - rotating the infant's body. Doctors should make a cut when they don't have enough room to manipulate the baby that way, they said.
They said the episiotomy puts the mother at increased risk for infections, bleeding and painful intercourse.
Hartmann said routine episiotomies could go the way of routine hysterectomies, which declined in the 1970s and 1980s when women armed with new information began to challenge their doctors.
"Almost all practice patterns take decades to change," she said. "This may change more quickly because of the awareness of the general public."