Does episiotomy increase perineal laceration length in primiparous women? - POEMs

Journal of Family Practice, Dec, 2001 by Amy C. Denham, Valerie J. King

Nager CW, Helliwell JP. Episiotomy increases perineal laceration length in primiparous women. Am J Obstet Gynecol 2001; 185:444-50.

* BACKGROUND Episiotomy was initially used based on theoretical benefit, with little evidence supporting claims that it prevented severe perineal lacerations or pelvic floor dysfunction. As principles of evidence-based medicine have begun to influence obstetrical practice, the utility of routine episiotomy has been called into question. Several observational studies have suggested that episiotomy increases the risk of third-and fourth-degree lacerations. A recent Cochrane review of 6 randomized controlled clinical trials comparing routine versus restricted use of episiotomy showed that episiotomy was associated with more second-degree perineal trauma, without significant differences in dyspareunia, severe perineal trauma, or severe pain. Although all but one of the trials included in the review used mediolateral episiotomy, the one randomized trial conducted in North America (which used midline episiotomy) showed similar results. Despite these data, episiotomy remains a common practice performed in more than 40% of deliveries in the United States.

* POPULATION STUDIED The authors of this study enrolled 80 pregnant women at term who had not had previous vaginal deliveries. The 62 who went on to have vaginal deliveries were included in the analysis. The participants' mean age was 26.3 years. The majority (92%) had prenatal care, and most (88%) had epidural analgesia during labor. Approximately one fourth of the women (28%) had forceps or vacuum-assisted delivery. A few had malpresentations, with 6% in the occiput posterior position.

* STUDY DESIGN AND VALIDITY This small observational study looked at a range of variables hypothesized to be related to perineal laceration length, including maternal demographics, size of genital hiatus and perineal body, fetal size and presentation, duration of second stage of labor, level of experience of birth attendant, operative vaginal delivery, and episiotomy. After delivery, one of the study authors measured perineal laceration length, and for 10 patients 3 additional observers measured laceration length to assess interrater reliability. Observers were blinded to one another's measurements but not to the other variables included in the analysis. The authors used logistic regression and Mann-Whitney U test to determine which variables were associated with laceration length.

This study was not adequate to establish a causal link between episiotomy and laceration length. A small observational study could be helpful in suggesting which variables might be associated with perineal laceration length, but a large randomized controlled trial would be necessary to establish definitively whether episiotomy increases laceration length. In this study, the decision whether to perform an episiotomy was left to clinical judgment, and the reader has no information on how this judgment was made. An unmeasured variable may have influenced both the decision to perform episiotomy and the length of laceration. Because of its small size, the study did not have the statistical power to uncover associations between other variables and laceration length.

* OUTCOMES MEASURED Perineal laceration length was the primary outcome measured in this study. The authors also assessed laceration severity. The study did not include variables relevant to quality of life, such as healing complications, severity of pain, duration of symptoms, dyspareunia, or incontinence.

* RESULTS Of the 62 patients in the final analysis, 76% had a perineal laceration, with a median length of 4 cm. Five patients (8%) had a third-degree laceration, and one patient (2%) had a fourth-degree laceration. Approximately half (44%) had an episiotomy. The mean laceration length was 3 cm longer for patients who had an episiotomy (4.9 cm vs 1.9 cm; P < 001). Patients who had a forceps- or vacuum-assisted delivery had a longer average length of laceration, but this association was not independent of episiotomy. When assisted deliveries were excluded from the analysis, the association between episiotomy and laceration length remained significant.

RECOMMENDATIONS FOR CLINICAL PRACTICE

This study provides weak evidence that episiotomy increases perineal laceration length in primiparous women. Earlier higher-quality trials provide strong evidence that episiotomy should not be performed routinely. Its use should be restricted to situations in which specific clinical indications exist. In some institutions episiotomy remains common practice despite data that have been available for more than a decade showing that it does not improve outcomes. This suggests the need for further educational interventions on how to attend deliveries in primiparous women without using episiotomy.

Amy C. Denham, MD, MPH
Valerie J. King, MD, MPH
Department of Family Medicine
University of North Carolina at Chapel Hill
E-mail: amy_denham@med.unc.edu