Episiotomy has been described as the most common operation in obstetrics.1 Studies of perineal trauma and morbidity associated with vaginal delivery and the use of episiotomy demonstrated an increased incidence of third- and fourth-degree tears with the use of episiotomy.2–5
The rationale for use of episiotomy was to minimize perineal damage and pelvic floor relaxation and to offer protection for the newborn from either intracranial hemorrhage or intrapartum asphyxia by decreasing second-stage dystocia. However, routine use of episiotomy was established without evidence to support its benefit. In fact, episiotomy with extension through the sphincter and rectal mucosa has been associated with significant morbidity.4–9 Damage to the anal sphincter is the most frequent perineal condition resulting in serious long-term sequelae after vaginal delivery. In a study by Haadem et al,10 nearly half of women with anal sphincter rupture experienced persistent symptoms, including flatal incontinence, dyspareunia, and perineal pain. Sultan et al11 noted that external sphincter damage occurred only in the presence of a tear or episiotomy.
Given the limited data on which to base clinical decisions, we sought to determine the outcome to the perineum in deliveries after a previous third- or fourth-degree laceration by examining the incidence of repeat third- or fourth-degree lacerations when delivery was managed with or without episiotomy or instrumentation.
Materials and Methods
The delivering attendant recorded use of episiotomy and evaluation of laceration or trauma. First-degree lacerations involve only the vaginal mucosa. Second-degree lacerations extend into the perineal body. Third-degree lacerations extend into the anal sphincter. Fourth-degree lacerations extend through the rectal mucosa. In the present study, severe laceration was used to identify third- or fourth-degree extension or tear. No laceration was used to identify both episiotomy without extension and first- or second-degree tears.
Using a perinatal database that has been prospectively maintained at our institution, we analyzed the records between 1978 and 1995 of nulliparas whose first birth was longer than 36 weeks' gestation, vaginal singleton, vertex presentation, birth weight greater than 2500 g, and who had a subsequent delivery at our institution. Patients were subdivided into those who sustained a third- or fourth-degree perineal laceration during their first delivery and those who did not. Variables included maternal age and weight at the time of delivery, birth weight, use of instrumentation, and episiotomy during the first birth. The subsequent delivery was analyzed for maternal age and weight at delivery, birth weight, gestational age, method of delivery, use of episiotomy, and occurrence of a severe laceration.
Comparison of data was done by Fisher exact and unpaired two-tailed t tests where appropriate. A difference was considered significant if P < .01.
There were 4015 women who met our starting criteria of nulliparity, gestational age greater than 36 weeks, singleton, and vertex presentation who had a subsequent delivery at our institution. Seven hundred seventy-four (19.3%) had a severe perineal laceration. Delivery characteristics of these women are shown in Table 1. There was no difference in the maternal age and weight at delivery between women who had a severe perineal laceration and those who did not. The average birth weight, use of instrumentation, and episiotomy were significantly higher in women who had a severe laceration.
Analysis of subsequent deliveries is shown in Table 2. There was no significant difference between the median age, weight, gestational age, average birth weight, spontaneous vaginal delivery, or cesarean delivery of these women. Midline episiotomy was used in 97% and mediolateral episiotomy in 3% of the cases in both groups. Women with a previous laceration were at increased risk of having an instrumental vaginal delivery and episiotomy. They were at more than twice the risk for a repeat severe perineal laceration. Severe laceration occurred in 161 women (4.0%) during their second delivery, indicating that nulliparity is a significant risk factor (P < 0.001, odds ratio [OR] 5.7, 95% confidence interval [CI] 4.8, 6.8).
We also examined the relationship of episiotomy and instrumental vaginal delivery in women with and without a history of severe perineal laceration (Tables 3 and 4). Episiotomy was a significant risk factor for a laceration in women with and without a previous laceration. The women at highest risk were those who sustained a laceration in their first delivery and had instrumental vaginal delivery with episiotomy in the subsequent delivery (21.4%). However, 19.0% of women without a laceration in their first delivery had one in the subsequent delivery if an episiotomy and instrumental vaginal delivery were performed. When episiotomy or instrumental delivery was done in the second vaginal delivery, 52 (11.6%) of 449 of women with a history of a severe perineal laceration had another, compared with 98 (6.5%) of 1509 without such a history (P < .001, OR 1.9, 95% CI 1.3, 2.7).
Physicians and midwives depend on their training and experience when faced with a decision to perform an episiotomy. Proponents claim that the proper use of midline episiotomy can minimize perineal and anterior vaginal wall damage, pelvic floor relaxation, and trauma to the neonate. However, midline episiotomy has been linked to significant morbidity, especially severe perineal laceration. Rectovaginal fistula, loss of rectal tone, perineal abscess formation, unsatisfactory anatomic repair, increased blood loss, excessive postpartum pain, and subsequent dyspareunia have all been associated with third- and fourth-degree lacerations.2,6–9 In the United States, in malpractice suits related to colorectal disease, iatrogenic sphincter injuries constitute one of five major categories; about half of these injuries are secondary to midline episiotomies.12,13
Because there is no indisputable evidence that episiotomy protects women from subsequent pelvic relaxation, its routine use has come into question.2–4 Numerous studies have demonstrated that midline episiotomy carries a higher risk of rectal injury than either mediolateral episiotomy or no episiotomy.4,13 Henriksen et al14 found that damage to the anal sphincter occurred twice as often in parturients when mediolateral episiotomy was used, with a frequency of 2%.14 Even the mediolateral approach has been associated with severe laceration compared with no episiotomy.
We sought to determine the outcome of the perineum in pregnancies subsequent to a third- or fourth-degree laceration. As shown in Tables 3 and 4, of women who sustained a laceration after episiotomy in their first delivery, 10.6% sustained a repeat laceration during subsequent normal vaginal delivery with episiotomy, and 21.4% had a repeat laceration when instrumentation was used with an episiotomy. Overall in this group, over 12% of the women had a repeat laceration with an episiotomy in their second vaginal delivery. Comparatively, only 2% of the women who did not receive an episiotomy sustained a repeat laceration. Although the effect of repeat episiotomy has not been reported, our results are comparable to those found in previous studies evaluating the risk of episiotomy in a heterogeneous population.2,5,14
Although this is a retrospective univariate study with its inherent problems, the data support previous studies in which the risks for perineal lacerations were associated with episiotomy and instrumental delivery. As mediolateral episiotomy was done in only 3% of women with a history of severe perineal laceration, our database was too small to determine whether that procedure is preferable to midline episiotomy.
The highest incidence of laceration occurred in women who had repeat episiotomy. Women with severe perineal lacerations in their first delivery were at 2.3 times the risk for sustaining lacerations during subsequent deliveries. Cutting an episiotomy was associated with a sixfold increased risk for a third- or fourth-degree perineal laceration in women who had vaginal deliveries. One fifth of women who had instrumental vaginal delivery with an episiotomy had a third-or fourth-degree laceration regardless of obstetric history. Our data support a reassessment of the use of episiotomy in contemporary obstetrics. This study provides important new information on the management of the perineum in subsequent deliveries in women with a history of severe laceration.
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