OBJECTIVE: We assessed whether women who had a perineal trauma (episiotomy or spontaneous tear of the second degree or higher) at the first delivery were at increased risk for spontaneous perineal tears at the next delivery, and whether the risk increases with the severity of previous perineal trauma.
DESIGN: Retrospective cohort study.
POPULATION: We included data from 1895 women who had their first and second deliveries at Saint-Sacrement Hospital, Quebec City, Canada, between 1985 and 1994. Our study was restricted to women who gave birth vaginally to a single living neonate at their first 2 deliveries and who did not have an episiotomy at the second delivery. We extracted the data from the Department of Obstetrics computerized database.
OUTCOMES MEASURED: Spontaneous perineal tears (of second degree or higher) at the second delivery.
RESULTS: Having a perineal trauma at the first delivery more than tripled the risk (relative risk=3.3; 95% confidence interval, 2.6-4.2) of spontaneous perineal tears at the second delivery. The risk of spontaneous perineal tears at the second delivery increased with the severity of previous perineal trauma at birth.
CONCLUSIONS: Our results show that the risk of spontaneous perineal tears at subsequent deliveries increases with the presence and the severity of perineal trauma at the first delivery.
Women frequently incur perineal trauma at delivery. Such trauma is associated with perineal pain that may still be present 3 months postpartum,1-4 dyspareunia,1,2 perineal infection,4,5 and following severe lacerations, fistula and incontinence of flatus and feces.6,7 Episiotomy accounts for a large proportion of perineal trauma. Wide variations exist in the use of episiotomy according to country,5 hospital,8 or birth attendant.1,9-12 There is no evidence that it is effective in preventing severe lacerations13,14 and pelvic floor relaxation1,7,13 or that recovery is more rapid and morbidity less than that following spontaneous tears.5,7 Also, median episiotomy increases the risk of severe perineal lacerations,14 particularly in primiparous women.10
Even in the absence of episiotomy, from 35%15 to 75%16,17 of women suffer a perineal trauma while giving birth. Risk factors include nulliparity,17,18 use of stirrups for delivery,19 second stage of labor of at least 1 hour,6,18,20-22 shoulder dystocia,21 forceps delivery,18,19,22-24 and excessive birth weight.20,21,23
Very few studies have assessed whether perineal trauma experienced during a first delivery is a risk factor for spontaneous tears at the next delivery. Observations from the West Berkshire randomized perineal management trial25 suggested that this could be the case, even though the results were not statistically significant. Of the 1000 women enrolled in that trial, 67% completed a questionnaire 3 years later, and 40% of the respondents had a second delivery in the interval. The women assigned to the “liberal” group (instruction to try to prevent a tear) tended to carry a higher risk of perineal tears at the next delivery than those assigned to the “restricted” group (to restrict episiotomy to fetal indications) [46% and 40%, respectively; P=0.3]. Two recent studies26,27 have reported an increased risk of severe perineal lacerations (third- and fourth-degree tears) in women who sustained such lacerations at their previous delivery, but these studies did not provide data on the whole range of perineal trauma.
Our objective for this retrospective cohort study was to assess whether the presence and severity of perineal trauma (defined as a spontaneous tear or an episiotomy with and without extension) at the first delivery are related to the risk of spontaneous perineal tears of the second degree or more in women who subsequently deliver vaginally without an episiotomy.
Methods
We included women who gave birth to their first and second baby at Saint-Sacrement Hospital of the Centre hospitalier affilié universitaire de Québec, Canada, between January 1, 1985, and December 31, 1994. Those who had a cesarean delivery, a multiple birth, or a stillbirth at either the first or second delivery were excluded, as were those who had an episiotomy at the second delivery.
We abstracted the data from the computerized database maintained by the Department of Obstetrics since 1985. The delivery physician routinely recorded data about labor and delivery on a standard form after the delivery. The attending physician indicated on the standard form whether the woman had no tear, a first-degree tear (limited to the fourchet, the perineal skin, and the vaginal mucosa), a second-degree tear (extending to perineal muscles but saving the anal sphincter), a third-degree tear (involving muscles of the central nucleus and the anal sphincter with anal mucosa remaining intact), a fourth-degree tear (complete rupture of the anal sphincter through the mucosa),28 or an episiotomy (with or without a third- or fourth-degree extension). Except for some first-degree tears, all other trauma required a surgical repair. The decision to cut an episiotomy was left to the discretion of the physician. The standard form also included information on factors potentially related to perineal tears, such as maternal age, epidural use, use of forceps or vacuum, shoulder dystocia, fetal presentation, gestational age (based on last menstrual period or on ultrasound dating, if the 2 estimations differ by more than 10 days), birth weight, head circumference of the newborn, and the training (obstetrics and gynecology or general or family medicine) and identity of the birth attendant. Data from these forms were computerized periodically by one obstetrician (J.J.P.). Incomplete or inconsistent data were checked using the medical records.