WASHINGTON, DC — Mediolateral episiotomy during operative vaginal delivery significantly reduces the risk for obstetrical injury, a large database study has found.

The results highlight an international divide, because most episiotomies performed in the United States and many in Canada are midline procedures. This is because of concern that mediolateral episiotomies cause more pain, session moderator Steven Swift, MD, from the Medical University of South Carolina in Charleston, told Medscape Medical News.

In the retrospective cohort study of 170,974 operative vaginal deliveries from the Netherlands Perinatal Registry, primiparous and multiparous women and forceps and vacuum deliveries were examined.

In all cases, the risk for injury was significantly lower when mediolateral episiotomy was performed. The difference was particularly striking for primiparous women during forceps deliveries.

Mediolateral episiotomy is the approach usually used in the Netherlands, and midline episiotomies were excluded from the analysis.

"In women with operative vaginal delivery, the use of mediolateral episiotomy reduces the risk for obstetrical anal sphincter injuries," Jeroen van Bavel, MD, from Amphia Hospital in Breda, the Netherlands, said here at the American Urogynecologic Society and International Urogynecological Association 2014 Scientific Meeting.

Given the serious morbidity of these third- and fourth-degree perineal tears, "a mediolateral episiotomy is the standard procedure in operative vaginal deliveries in our hospital," Dr. van Bavel said.

Investigators controlled for parity, induction of labor, augmentation with oxytocin, use of pain medication, duration of the second stage of labor, indication for intervention during delivery, fetal position, and birthweight.

Table. Injury Rates During Delivery

Women Mediolateral Episiotomy, % No Mediolateral Episiotomy, % Adjusted Odds Ratio 95% Confidence Interval
Vacuum delivery        
   Primiparous 2.5 14.0 0.14 0.13–0.15
   Multiparous 2.1 7.5 0.22 0.20–0.25
Forceps delivery        
   Primiparous 3.4 26.7 0.09 0.07–0.11
   Multiparous 2.6 14.2 0.14 0.09–0.23


For vacuum deliveries, the number of mediolateral episiotomies needed to prevent 1 case of obstetrical anal sphincter injury would be 8 for primiparous and 18 for multiparous women. For forceps deliveries, the number needed to prevent 1 injury would be 4 for primiparous and 8 for multiparous women.

Large Numbers, Tight Confidence Intervals

"The study had incredibly large numbers and tight confidence intervals, almost unheard of in our field of medicine," Dr. Swift told Medscape Medical News. "But it's also a perinatal database, so it's all about the child. The data are not really focusing on the mother. If you had a database that was focused on the mother and the delivery process, you would carry it forward at least to the 6-week visit to see how patients are doing."

Dr. Swift said he would like to know more about whether the women had any other injuries or experienced problems after delivery, particularly with pelvic function and vaginal pain.

The literature comparing levels of pain and dyspareunia after midline and mediolateral episiotomies is out of date, explained study investigator Jan Willem de Leeuw, MD, from Ikazia Hospital Rotterdam, the Netherlands. Closure using the newer technique of continuous suturing — particularly if carried through all layers (vagina, perineal muscles, and skin) — is associated with far less pain than the old technique using intermittent sutures, according to a 2012 Cochrane review (Cochrane Database Syst Rev. 2012;11:CD000947), he reported.

However, Dr. Swift noted that, "in America, we have a bias and a prejudice against mediolateral episiotomies." He said he won't be swayed without more data.

Still, "it's a wonderful study. The numbers are phenomenal and it shows that mediolateral episiotomies really do protect the anal sphincter," Dr. Swift said.

The ideal study would look at a similarly large population and compare patients who had mediolateral episiotomies with those who had midline episiotomies, and would follow them for up to 6 months to assess injury, discomfort, and dyspareunia, he explained.

But Dr. de Leeuw pointed out that such a study would be considered unethical on both sides of the Atlantic. "It's unethical to do a trial of mediolateral vs midline in the United States because of pain, and in Europe it's unethical because of the chance of injury — that's the catch-22 situation that we're in."

International Divide

Dr. Swift pointed out that the Dutch group could at least follow women after mediolateral episiotomy using the modern continuous suturing technique to see if the postpartum rates of dyspareunia and pelvic pain are lower than levels reported using the old intermittent suturing. "If incidence is 2% or 1% or 0.5%, that would be very powerful and would debunk the myth and get rid of the prejudice," he said.

Such a study is currently underway by Dr. de Leeuw's team. They are also attempting to compare pain scores after surgery with those of women who have had spontaneous ruptures. "We feel it's necessary to know. Every time I come to the United States and Canada, I have this discussion," Dr. de Leeuw reported.

I personally don't think a midline episiotomy is the right thing. I always do a mediolateral.

Dr. de Leeuw acknowledged that "there is a tradeoff; you need to do more episiotomies to prevent 1 obstetrical anal sphincter injury. We're trying to develop some sort of risk calculator. I think that's the way of the future so you can counsel your patient on the risks."

"I see lots of women with fecal incontinence after obstetric tears. It's devastating," he added. "Primary prevention is the only thing you can do."

"I personally don't think a midline episiotomy is the right thing. I always do a mediolateral," said Stephen Jeffery, MBChB, head of the Department of Urogynecology and Pelvic Floor Reconstruction at Groote Schuur Hospital and the University of Cape Town in South Africa, who was not involved in the study.

Dr. Jeffery, who worked in London, United Kingdom, for 5 years, told Medscape Medical News that he typically does a continuous suture for the deep layers, and then a continuous suture for the vagina. In cases of excessive bleeding, he occasionally uses interrupted stitches. But he always uses the mediolateral approach, avoiding the anal sphincter.

"In my opinion, midline has a much greater likelihood to extend into the anus, so you would have a higher chance of incontinence. The minute the tear goes into the sphincter, there's more dyspareunia and pain," he explained.

Dr. Jeffery said the heavy reliance on midline episiotomy in North America puzzles him. "If it was up to me, I would be very keen to continue doing mediolateral episiotomies rather than midlines," he said.

Dr. van Bavel, Dr. de Leeuw, and Dr. Swift have disclosed no relevant financial relationships. Dr. Jeffery has received speaker fees, travel grants, surgical training, and support to run local workshops from Boston Scientific, Bard, Coloplast, Karl Storz, and Covidien.

American Urogynecologic Society (AUGS) and International Urogynecological Association (IUGA) 2014 Scientific Meeting. Presented July 23, 2014.


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