Advocates of the liberal use of episiotomy have hypothesized that the procedure has many benefits, including:
Most studies do not provide strong support for these claims.
Utilization has declined. Over the past decades, the liberal use of episiotomy has given way to a pattern of practice that emphasizes restricted use.1-4 In the 1980s, in the United States, episiotomy incisions were performed in approximately 40% of vaginal deliveries5; in 2010, the rate at most obstetric facilities was <10%.
When the episiotomy rate was 40%, a median incision made sense: A very limited incision was sufficient to provide extra room for the passage of an average-sized fetus through an average-sized birth outlet. With the rate below 10% today, however, the likelihood is greater that episiotomy is being reserved for cases in which a significant clinical problem exists—most often, mismatch between the birth outlet and fetal size—and the appropriateness of median episiotomy comes into question. By restricting episiotomy incisions to the most complex clinical situations, the risk is greater that the episiotomy will be associated with a severe perineal laceration, such as a laceration of the anal sphincter (third-degree) or the rectal mucosa (fourth-degree)—or both.
A spotlight on severe lacerations. Over the past decade, practitioners of obstetrics have refocused attention on reducing the risk of third- and fourth-degree perineal lacerations—severe injuries that are associated with significant maternal morbidity. Clinical variables that increase the risk of a third- or fourth-degree perineal laceration include:
- forceps delivery
- median episiotomy
- persistent occiput posterior position.6
Many studies have reported that a median episiotomy is associated with a higher rate of third- and fourth-degree lacerations than either 1) deliveries without an episiotomy or 2) deliveries with a mediolateral episiotomy.1,7-9 With the modern practice of reserving episiotomy for the most complex vaginal deliveries and renewed attention to reducing the rate of third- and fourth-degree lacerations, the time has come for us to stop using the median episiotomy and switch to using a mediolateral episiotomy incision.
STOP: using the median episiotomy
Numerous studies have reported that the median episiotomy is associated with an increased risk of laceration of the anal sphincter (third-degree) and rectal mucosa (fourth-degree), compared with mediolateral episiotomy.
Randomized study of incisions. In a clinical trial, 407 nulliparous women were randomized to median or mediolateral episiotomy incision.10 The incisions were made at a time during the second stage of labor that was judged by the clinician to be most appropriate—typically immediately before delivery of the fetal head.
To perform mediolateral episiotomy, clinicians in this study used a pair of straight scissors to make an incision that began in the midline and was carried to the right side of the anal sphincter for 3 to 4 cm, at an angle >45°. Median episiotomy was performed by incision of the perineal tissues for 2 to 3 cm, directly in the midline.
The clinical protocol resulted in more women assigned to mediolateral episiotomy (n=244) than to the midline episiotomy (n=159), but the two groups were well matched on such major clinical characteristics as age, gestational age at delivery, duration of the second stage, rate of operative delivery, and anesthesia used.
Compared to what was found with mediolateral episiotomy, the median episiotomy incision was associated with a statistically significant increase in the frequency of complete third-degree tears (median, 6.1%; mediolateral, 1.6%) and fourth-degree tears (median, 5.5%; mediolateral, 0.4%).
Further comparisons. Many clinicians avoid mediolateral episiotomy. Why? Because, compared with median episiotomy, a mediolateral incision is believed to be associated with greater postpartum pain, increased severity and incidence of dyspareunia, and more disfiguring scars.11
But subjects in the randomized trial that I just described, in which mediolateral and median episiotomy were compared,10 reported postpartum pain, postpartum use of pain medicine, and impaired bowel function at similar rates regardless of the type of incision.
Investigators determined that, in the first month after delivery, more women who had a median episiotomy resumed vaginal intercourse (18.1%, compared to 6.3% who had a mediolateral incision). In the second month after delivery, however, women in both the median and mediolateral episiotomy groups reported similar resumption of sexual intercourse (median, 82.8%; mediolateral, 80.8%).
Three months after delivery, physical examination determined that a higher percentage of subjects in the median incision group (43%) had what was judged to be a “good” appearance to the scar (compared to 27% in the mediolateral group). Last, subjects in the median group had a higher rate of perineal laxity (7%) than did women in the mediolateral group (1.6%).
START: using a mediolateral incision when episiotomy is necessary