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Objective

This study aimed to assess the association between episiotomy and measures of pelvic organ prolapse quantification system (POP-Q) in a cohort of women with vaginal parturition.

Study design

A prospective study was conducted with 549 eligible patients with vaginal delivery history. Women who were pregnant, gave birth within the preceding 6 months period, had a known history of pre-pregnant prolapse, had a history of hysterectomy or any operation performed for pelvic organ prolapsus and stress urinary incontinence, refused to participate and to whom POP-Q examination could not be performed (due to anatomic or orthopedic problems) were excluded. Patients were categorized as women with episiotomy and without episiotomy. The degree of genital prolapse was assessed by using POP-Q system. The effect of episiotomy on overall POP-Q stage and individual POP-Q points was calculated with logistic regression.

Results

439 patients had a history of episiotomy whereas 110 patients had no episiotomy. 38.2% of women without an episiotomy, and 32.0% of women with episiotomy had genital prolapse determined by POP-Q system. There was no statistically significant association between episiotomy and POP-Q stage (AOR, −0.24; 95% CI, −0.65–0.18, P = 0.26). Episiotomy was found among the independent predictors for certain POP-Q points such as Bp, perineal body (pb) and total vaginal length (tvl). Episiotomy was negatively correlated with prolapse of Bp and with pb and tvl.

Conclusion

Episiotomy had an effect on certain POP-Q indices, but had no influence on overall POP-Q stage.

Keywords: Episiotomy, Pelvic organ prolapse, Pelvic organ prolapse quantification. 


1. Introduction
Pelvic organ prolapse (POP) is a common problem with a significant social and financial burden. More than 338,000 procedures for prolapse are performed annually in the United States [1]. Although several risk factors such as age, obesity, smoking, menopause, connective tissue disorders and genetics have been described, obstetric trauma, especially vaginal parturition has been suggested as the most important factor in the pathogenesis of urogenital prolapse [2] and [3].

Episiotomy was performed liberally until late 1980s with a belief that it prevented excessive perineal damage which might lead to pelvic relaxation later in life [4]. However, aftercoming randomized controlled studies asserted that episiotomy could not provide the maternal and fetal benefits reported by its proponents [5], [6], and [7]. It has even been shown to subject the patient to increased risk of perineal body injury and anal sphincter damage [8]. As a result of increased concern and evidence, American College of Obstetricians and Gynecologists (ACOG) has eventually recommended restricted use of episiotomy in selected patients [9]. The effect of episiotomy on pelvic floor (PF) function has been investigated on several questionnaire-based studies [10] and [11]. A meta-analysis that collected the findings of these studies reported that episiotomy, either median or mediolateral, did not associate with reduced risk of PF dysfunction related complaints such as self-reported involuntary loss of urine, incontinence of stool or flatus, and sexual dysfunction [12].

Pelvic organ prolapse quantification (POP-Q) system was introduced in 1996 by International Continence Society (ICS) to allow researchers to report their findings in a standardized fashion and to diminish the intra- and interobserver variability [13]. Although the functional and electrophysiological outcomes of episiotomy on the PF function are evaluated in a number of studies, there is no study regarding the anatomic effects of episiotomy on PF. For this reason, we performed POP-Q system in a cohort of women who delivered vaginally.

 
2. Materials and methods
This prospective study was designed to assess all the eligible women admitted to gynecology clinics for a six-month period (June 2008–December 2008) who had a history of at least one vaginal birth with or without an episiotomy and whose birth records were attainable. Women who were pregnant, gave birth within the preceding 6 months period, had a known history of pre-pregnant prolapse, had a history of hysterectomy or any operation performed for POP and stress urinary incontinence, refused to participate and to whom POP-Q examination could not be performed (due to anatomic or orthopedic problems) were excluded. Women were considered to have episiotomy if they had episiotomy in any vaginal delivery. A total of 549 patients with an age range of 19–70 consisted the study group. The study protocol was approved by the Ethics Committee of University of Mersin, and each subject gave written informed consent.

Subjects were questioned to provide the practitioner with a summary of the patient's medical, surgical, family, and social history and included questions that are relevant to current prescriptions (hormonal therapy, anti-diabetics, anti-hypertensives, medications for overactive bladder or constipation), habits (smoking) and allergies, medical conditions (diabetes mellitus, chronic hypertension, cardiopulmonary diseases), surgical, obstetric, gynecologic, and social history. Detailed information on obstetric history was collected by interview and hospital records. The information about the type of episiotomy was collected from the hospital records and pelvic examinations. The most commonly used and taught methods of episiotomies in Turkey are as follows: episiotomies are performed when the perineum is bulging and when about 4 cm of fetal scalp is visible during a contraction. The incision is placed at 7 o’clock position for mediolateral episiotomies and extend about 4 cm the direction of the right ischial tuberosity at an angle of 45 degrees to the vertical line. For midline episiotomies, the perineum is incised about one-half the length of perineum from the midline of the posterior fourchette toward the anus [8]. Anthropometric measures were recorded before the vaginal exam. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared. Waist-to-hip ratio (WHR) was calculated by dividing circumferences of waist to hip. Ethnic differences were not addressed because the patients have a similar ethnic background.

All examinations were performed by ET, DE, or under the supervision of these authors with a ruler. The staging of POP conformed to the standards and terminology set forth by the ICS [13]. An overall stage was assigned to each patient, according to the most severely prolapsing compartment.

Because no data have been published previously on the effect of episiotomy on POP-Q stages, the study power was based upon predicted changes in the percent of POP, using data derived from the literature [3]. Based on the suggestion that episiotomy would be protective against POP and assuming an approximate incidence of 30% of any degrees of POP and 1.5 times lower incidence in women with episiotomy, 175 patients in each group would be sufficient to detect a difference at a significance level of 5% with a power of 80% (G*Power v2.0). However, during the 6 months study period instead of 175 patients, only 110 patients without episiotomy could be gathered as there was a trend to perform routine episiotomy for delivery in the previous years. All statistical analyses were performed using SPSS v17.0 (SPSS Inc., Chicago, IL) for Windows (Microsoft, Redmon, Washington). The baseline characteristics were compared by using Student's t test for continuous variables and X2 or Fischer exact test for binary data. The POP-Q index values of the groups were compared by Student's t test. Stepwise multiple linear regression analyses were performed to find out the independent effects of episiotomy on each POP-Q indices. The effects of episiotomy on POP-Q stages were calculated using ordinal regression analyses after adjustment for possible confounders as listed in Table 3. A P value ≤ 0.05 was considered statistically significant.

 
3. Results
A total of 549 eligible patients with a history of vaginal delivery − 439 with and 110 without episiotomy – were enrolled. Baseline characteristics of the patients were summarized in Table 1. The mean BMI and WHR in episiotomy group were significantly lower than in women without episiotomy (P = 0.001 and P = 0.04, respectively). The smoking rate was significantly higher in episiotomy group than in women without episiotomy (26.9% vs. 16.5%, P = 0.03). The mean parity of women without episiotomy was higher than of women with episiotomy, but, the difference did not reach statistical significance (Table 1). The rate of instrumental delivery (2.7% vs. 8.7%, P = 0.02) and the rate of anal sphincter injury (5.5% vs. 9.8%, P = 0.04) were significantly higher in women with episiotomy than in women without episiotomy (Table 1). Regarding POP-Q indices, the measurements of Aa, Ba, C and D points were comparable between the groups (P > 0.05, Table 2). However, the position of Ap point was significantly higher (−2.46 ± 0.95 vs. −2.24 ± 1.05, P = 0.03), and the measurements of genital hiatus (gh), perineal body (pb) and total vaginal length (tvl) were significantly lower in episiotomy group than in non-episiotomy group (P < 0.05, Table 2). Furthermore, episiotomy was found among the independent predictors of pb and tvl measurements by stepwise multiple linear regression analyses. Although there was a marginal significance in univariate analysis when comparing the position of Bp point of episiotomy-positive patients with episiotomy-negative patients (−2.66 ± 1.07 vs. −2.88 ± 1.08, P = 0.06), multiple regression analysis revealed that episiotomy was also an independent predictor of Bp point with parity in determining the position of Bp. Other independent predictors for each point are summarized in Table 2.

The distribution of POP-Q stages between the groups was presented in Table 3. After adjustment for age, BMI, WHR, menopausal status, tobacco use, educational and socio-economical status, gravidity, parity, age at first birth, maximum birth-weight, instrumental delivery and anal sphincter injury; the relationship between episiotomy and POP-Q stage was not significant (AOR, −0.24; 95% CI, −0.65–0.18, P = 0.26, Table 3). The independent predictors of POP-Q stage were determined as parity (AOR, 3.21; 95% CI, 1.24–7.39, P = 0.02), maximum birth-weight (AOR, 1.12; 95% CI, 1.02–3.09, P = 0.05), menopause (AOR, 1.6; 95% CI, 1.36–1.99, P = 0.03) and WHR (AOR, 2.8; 95% CI, 1.16–5.37, P = 0.03) (Table 4). In Table 5 the distribution of stage ≥ 2 prolapse with respect to compartments was depicted. No significant difference was observed with respect to rates of anterior, posterior or central stage ≥ 2 prolapse between patients with and without episiotomy.

POP-Q, Pelvic organ prolapse quantification.

The relation was adjusted for age, body mass index, waist-to-hip ratio, menopausal status, tobacco use, educational and socioeconomical status, gravidity, parity, age at first birth, maximum birth weight, instrumental delivery and anal sphincter injury.

 
4. Comment
In the present study, it was found that episiotomy had an effect on certain POP-Q indices, but had no influence on overall POP-Q stage. Episiotomy was negatively correlated with prolapse of Bp and with pb and tvl measurements. Parity, the maximal birth weight, the menopause and WHR were independent predictors for POP-Q stage, however, episiotomy had neither protective nor causative effect on POP determined by POP-Q system in the cohort of this study composed of women who delivered vaginally.

Although POP is a common problem, the studies on its incidence revealed conflicting results. This condition is largely due to differences in the definition and the measurement techniques of genital prolapse. We observed that 38.2% of women without an episiotomy, and 32.0% of women with episiotomy had POP according to the definition of prolapse as POP-Q stage ≥ II by ICS (P > 0.05, Table 3). Former studies which generally used Baden–Walker classification reported an incidence of about 30–50% of genital prolapse in women [14] and [15]. In a recent study from Turkey the rate of isolated anterior prolapse which was defined as protrusion of anterior vaginal wall at or beyond the hymenal ring (POP-Q, stage ≥ II) was found to be 33% and 38% in women with and without episiotomies respectively. In the same study mixed type prolapse was observed in 32% and 28% in patients with and without episiotomies [16].

In the current study, no statistically significant relationship was found between episiotomy and general POP-Q stage in women who delivered vaginally. In their systematic review Hartmann et al. reported that the impact of episiotomy on the development of prolapse remains unknown [12]. Handa et al. in their recent study reported that no increase in prolapse was seen in association with episiotomy. Instead these investigators found a potential association between spontaneous laceration and prolapse in vaginally delivered women 5–10 years after first delivery [17]. Tegerstedt et al. [18] compared 197 women with episiotomy to women without episiotomy and found 1.7 times (95% CI, 1.2–2.4) increased risk for genital prolapse. However, the most important problem in this study is the inclusion of women with Caesarean section (C/S) in the group of women without episiotomies. Keeping in mind that C/S has a protective effect on pelvic organ prolapse, [2] the inclusion of patients with C/S in the group of women without an episiotomy erroneously leads to the conclusion that episiotomy increases the risk of POP. That is why we think that inclusion of women with vaginal parturition in the current study reflects the real effect of episiotomy on POP prevalence.

In their retrospective study Cam et al. reported a significantly lower rate of central defects which was defined as the presence of a central bulge and diminished vaginal rugae on the anterior vaginal wall in women with a history of mediolateral episiotomy than in the others (21% vs. 38%, respectively, p = 0.009) and suggested that mediolateral episiotomy prevents central defects [16]. Similarly in the present study prolapse of Ap point was found to be significantly lower in the episiotomy group when compared with the control (−2.46 + 0.95 vs −2.24 + 1.05 respectively, p = 0.03); however, episiotomy was not found to be an independent predictor of prolapse of Ap in the regression analysis. Instead rather than episiotomy, BMI, parity, and menopause status were found to be independent predictors of Ap.

Trowbridge et al. [19] searched the measurements of POP-Q indices in a general cohort. They observed that the degree of prolapse of Bp point was increasing with the number of vaginal births. We found that the degree of prolapse of Bp point was higher in women with episiotomy, even after correction for possible confounders, especially the parity. These observations point out that the episiotomy may not be protective, rather may have incremental effect on the prolapse of Bp point. Although there are several hypotheses, the functional and anatomical relations of pelvic organ support are not completely understood. According to the 3-level support hypothesis, the support of Bp point is supplied by level II. The level II is composed of mainly pubocervical and pubovesical ligaments which are responsible for the support of vagina, rectum and bladder [20]. However, none of these anatomic parts are injured with episiotomy incision. Actually, episiotomy incision disrupts the integrity of Denonvillier fascia (rectovaginal septum) which's role is not much mentioned in the pelvic organ support. Denonvillier fascia is also a part of endopelvic fascia that extends from the perineal body upward and continues with the puborectal ligament [21]. It is possible that the disruption of this structure by episiotomy may lead to the prolapse of Bp point.

The pb is the central point for the attachment of the perineal musculature, and lies beneath and supports the pelvic diaphragm. It is suggested that the failure to reattach the endopelvic fascia to the pb at the time of vaginal delivery leads to POP [22]. The width of pb was shown to decrease with the number of vaginal births in the study of Trowbridge et al. [19] However, they did not consider the episiotomy state of the subjects. We found a significant inverse association between the presence of episiotomy and the size of pb in multivariate analysis. The women with episiotomy had significantly smaller mean pb measurement than women without an episiotomy (3.15 ± 0.85 vs. 3.33 ± 0.72, P = 0.04, Table 2). It seems that the size of pb reduces with the number of vaginal deliveries, and episiotomy causes further diminishment. The role of pb in the anatomic and physiologic support of pelvic organs have been emphasized in a number of reviews [22] and [23]; however, the importance of the size of pb in POP-Q system remains to be clarified.

We observed a significant association between episiotomy and the width of gh in univariate; and tvl in uni- and multivariate analyses. Although the importance of these measurements is not clear, there are previous studies suggesting a correlation between the vaginal delivery and the width of gh [24]. We think that the negative association of tvl and gh with episiotomy may result from Cicatrisan process of this intervention.

There are several limitations of this study. One of the limitations of the study that could not be controlled was that the episiotomies had been performed by different doctors during the deliveries of the women and the method of episiotomy might not have been exactly the same. As another limitation, like in other European countries, mediolateral episiotomy was the most performed episiotomy type. There were only 31 patients (7.1%) with median episiotomy, and they were assessed with mediolateral episiotomy group, together. Furthermore, we included only women with intact uterus to observe the effect of episiotomy on the natural history of POP. Another important limitation was the under power (61.1%) of the study. Studies with larger sample sizes are necessary.

In conclusion, although episiotomy did not change overall POP-Q stage, it had certain negative effects on several POP-Q indices. That is why, before conclusion that episiotomy had no protective or causative effect on POP, the productivity of this staging system and the effects of episiotomy on individual points on genital support should be argued in the future.

 
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