The practice of delivering babies has long been influenced by traditions, based on the theories of popular obstetricians rather than on scientific proof.
Recently, though, some routine practices have been put through the rigors of scientific testing and have been found ineffective at best and harmful at worst. One such procedure is the episiotomy, an incision that widens the vaginal opening to allow the baby's head to pass through.
For decades, a vast majority of women delivering babies were routinely given episiotomies, which involve painful recoveries and come with great risks of complications, including incontinence, later in life.
Now, at some of the leading teaching hospitals, obstetricians have virtually abandoned the practice. At other hospitals, episiotomy is still used, but the number of procedures has declined drastically.
Among woman having vaginal deliveries in hospitals, 64 percent had episiotomies in 1980 compared with 39 percent in 1998, a study published in the September issue of the journal Birth found.
"The science supporting routine use of episiotomy is marginal at best," said Dr. Andrew Helfgott, director of maternal fetal medicine at Sacred Heart Hospital in Pensacola. "It's a procedure that has been overutilized, whose benefits are not as pronounced as some would claim."
Recent studies have found that women who have episiotomies have greater risks of complications than those who do not.
An episiotomy is a 1- to 2-inch incision of the perineum, the area of skin and muscle behind the vaginal opening. First advocated in the United States in the 1920s, the episiotomy was believed to help prevent serious third- and fourth-degree lacerations to the perineum as the infant's head pushed through the birth canal. Such lacerations tear into the anal sphincter and can lead to temporary or longterm fecal incontinence.
An episiotomy was also thought to prevent relaxation of the pelvic floor muscles, a complication of childbirth that also contributes to urinary and fecal incontinence.
Last, because an episiotomy speeds the pushing stage of labor, doctors believed that it would prevent injury to the baby.
The procedure became widespread in the 1940s, when childbirth shifted from the home to the hospital. Until the late 1970s, practically all women delivering in hospitals had episiotomies. But at that point, women, midwives and some obstetricians started questioning its use. In 1983, two authors did a systematic review of the literature and found considerable evidence of risks associated with it. Since then, other studies have backed these findings.
"Most of the best data in the literature suggest that routine use of episiotomy only increases the incidence of serious lacerations involving the rectum and the anal sphincter," said Dr. Michael Greene, director of maternal-fetal medicine at Massachusetts General Hospital in Boston.
The birth study found that the incidence of serious tears was 3.6 percent in women who did not have episiotomies, but was 7.8 percent, more than double, in women who had episiotomies. Other studies have shown even higher rates of lacerations.
Most researchers agree that the risk of severe lacerations outweighs the benefits. When doctors do perform an episiotomy, they have a choice of two kinds of cuts. The first cut, called a midline episiotomy, goes straight back and is more likely to tear into the anal sphincter. The second type, a mediolateral cut, angles to the side and helps prevent tears to the anal sphincter and rectum in addition to long-term complications.
The tradeoff is that the mediolateral is more painful for the patient, and she faces a longer recovery. Over the decades the two types of incisions have reversed places, with mediolateral now ranking as the preferred procedure.