Although episiotomy is the most common surgical intervention in obstetrics, few studies explored its role in postpartum pelvic floor functioning. In the largest review of the 1990s, Woolley1 concluded that episiotomy prevents anterior perineal lacerations but does not achieve any of the benefits traditionally ascribed to the procedure: prevention of perineal damage, particularly urinary and anal incontinence, prevention of pelvic floor relaxation, and protection of the newborn from intracranial hemorrhage and intrapartum asphyxia. In regard to pelvic floor muscle strength, the author examined the data of 11 groups of investigators who have used objective, instrumented measurements of pelvic floor musculature or urinary sphincter strength to assess the changes caused by childbirth and episiotomy, but he found no evidence that episiotomy moderates the normal loss of pelvic floor muscle strength usually experienced after vaginal delivery. Wooley states that no research has found a persistent difference in objective pelvic floor strength between episiotomy and nonepisiotomy patients. In a study conducted by Klein et al,2 it was found that a policy of restricting median episiotomy use in primiparous women was associated with perineal trauma similar to that with the routine approach: the authors found no difference between trial groups in postpartum perineal pain, antepartum and 3-month-postpartum electromyographic perineometry, urinary and pelvic floor symptoms, or sexual outcomes. Röckner et al3 prospectively examined pelvic floor muscle strength in 87 women using vaginal cones and stated that their findings do not support the theory that routine episiotomy reduces the risk for damage to the pelvic floor muscles. A more recent review4 agrees that no conclusive evidence supports the routine use of episiotomy to prevent pelvic floor muscle damage.
Data about the role of mediolateral episiotomy on postpartum pelvic floor functioning are relatively scant, although it has been extensively considered in the prevention of severe perineal lacerations.5–7
The aim of this study was to evaluate the effect of mediolateral episiotomy on puerperal pelvic floor strength and dysfunction (urinary and anal incontinence, genital prolapse) compared with a population of nonepisiotomy primiparous women to determine whether the procedure is associated with a change in perineal functioning and whether it protects against urinary incontinence, anal incontinence, and vaginal prolapse.
MATERIALS AND METHODS
This study involved 519 consecutive primiparous women with singleton pregnancies and spontaneous vaginal delivery from May 2001 to December 2002 with the fetal head in occiput anterior position. All the women enrolled gave informed consent at discharge from the hospital (2–3 days postpartum) to evaluate pelvic floor function 3 months after vaginal delivery. Institutional review board (Istituto di Ricovero e Cura a Carattere Scientifico “Burlo Garofolo”) approval was previously obtained. All the women were residents of Trieste. The population of puerperae in our city (white Caucasian women) is very homogeneous because the phenomenon of immigration is mild. The management of the perineum in the second stage of labor did not differ among the women, because delivery is usually carried out in the lithotomy position. We excluded those patients who did not deliver in the lithotomy position (less than 5%). Other exclusion criteria were cesarean delivery, third- and fourth-degree perineal lacerations, preterm, breech, and operative delivery, anal and urinary incontinence that pre-existed vaginal delivery, and a history of vaginal or anal surgery. Considering that in our department there are about 1,700 deliveries per year (cesarean deliveries: about 20% in primiparas; primiparous women: about 50%), 50–55% of the women declined to participate in this study (patients of private physicians for the most part).
Puerperae were divided in 2 groups according to the assessment of perineal trauma: the first group (group A: 254 women, 48.9%) comprised the women who received mediolateral episiotomy; the second group (group B: 265 women, 51.1%) comprised the women with intact perineum (no lacerations) and spontaneous perineal lacerations (first- and second-degree). In particular, we found 82 women with intact perineum (30.9%), 127 women with first-degree perineal lacerations (47.9%), and 56 women with second-degree lacerations (21.1%). We found that, in the last 10 years in our department, mediolateral episiotomy was performed in 51.2% of primiparous women and 12.6% of multiparous women. We limited our analysis to nulliparous women, because it is among this group that the majority of perineal trauma is sustained. There were no selection criteria before the beginning of labor to perform mediolateral episiotomy.
Data related to labor and delivery were collected from medical records by a single trained abstractor. Women who were invited to participate in this study underwent an interview and a clinical assessment of pelvic floor function and strength. Careful histories were taken, with particular attention to the development of urinary and/or anal incontinence in puerperium. Stress urinary incontinence was diagnosed by the observation at the time of the visit of involuntary loss of urine from the urethra, synchronous with coughing (positive stress test) with a comfortably full bladder, according to the definition of the International Continence Society;8 urge incontinence, by the loss of urine associated with a strong desire to void, and anal incontinence by incontinence of flatus, liquid, or solid stool. Frequency was defined as voiding 7 or more times during the day and 2 or more times at night. Dyspareunia and perineal pain (pain during sitting, walking, or defecation and micturition) were recorded as absent, mild, moderate, and severe as in the article of Signorello et al.9
Clinical evaluation was previously described in a publication of this journal.10 Examination was performed with each woman in the lithotomy position, with the knees semiflexed. A scoring range of 0–5 was used according to the previously validated Oxford Scale.11 We considered abnormal those digital test scores less than 3.
Vaginal manometry was performed with each woman in the same position with a silicone sensor perineometer (PFX; Cardio Design Pty Ltd, Brisbane, Australia). Women were instructed to contract the pelvic floor muscles as strongly as possible, and the highest single reading was recorded. Manometric values were expressed in centimeters of water. We considered as abnormal perineometric values less than 12 cm of water.
The urine stream interruption test was performed with a uroflowmeter (UroDesk 300; SI.EM Sistemi Elettromedicali srl, Milano, Italy) according to the technique described by Sampselle.12 Each woman was asked to interrupt urine flow after a signal was given. The software of the uroflowmeter electronically measured the seconds from the signal to the complete cessation of urine flow (urine stream interruption test score). We considered as abnormal any urine stream interruption test scores greater than 5 seconds.
Urogenital prolapse was defined in accordance with the “Halfway System Classification” proposed by Baden and Walker.13 To simplify the presentation of the results, we defined segments 1 and 2 of the Baden and Walker classification as anterior prolapse, segments 3 and 4 as intermediate prolapse, and segments 5 and 6 as posterior prolapse.
Data collected were treated by using different analysis methods: quantitative-type variables were subjected to Student t test to verify the difference between the mean values of the same variable within the different subpopulations, whereas percentages were subjected to Fisher exact test. Using a simple logistic regression model to test an estimate of relative risk (RR), we expressed the odds ratio (OR) of every single variable considered with respect to the control population (group B).
Statistical evaluations were performed with the software program Stata 5.0 (Stata Corporation, College Station, TX). Statistical significance was set at P < .05.
The 2 groups were comparable for every variable considered, with the exception of neonatal weight, which was significantly higher in episiotomy group, and epidural analgesia, which was requested significantly more often in episiotomy group (Table 1).
With regard to the symptoms reported by the women, 201 puerperae of group B (75.8%) did not report any symptoms, and only 167 women in episiotomy group (65.8%) were absolutely asymptomatic; the likelihood of being completely asymptomatic was significantly higher in the nonepisiotomy group (P = .011). Stress urinary incontinence was reported by 33 women in group A (12.9%) and 32 puerperae in group B (12.1%) (Table 2); all the women presented with a positive stress test with a comfortably full bladder. Urge incontinence was present in 5 women of the episiotomy group (1.9%) and in 2 women in the nonepisiotomy group (0.7%) (P = .23). We did not find a difference either in the incidence of frequency and urgency (2 women in group A: 0.8%; 6 women in group B: 2.3%; P = .17) or in the incidence of dysuria (3 women in group A: 1.2%; 2 women in group B: 0.8%; P = .61). The incidence of anal incontinence was similar in the 2 study groups, even if in very few cases (group A: 7 women, 2.8%; group B: 5 women, 1.9%; P = .51). On the contrary, both dyspareunia and perineal pain were significantly higher in women who underwent episiotomy, even if we noted that perineal pain was always reported as “mild” (17 women in group A, 6.7%; and 6 in group B, 2.3%; P = .014), whereas dyspareunia was “mild” in 15 women (5.9%) in group A and in 7 women in group B (2.6%), and “moderate” in 5 women in group A (1.9%) and in 2 women in group B (0.8%).
No difference was noted between the groups in the incidence of prolapse (Table 3).
In Tables 4 and 5, we report the pelvic floor muscle assessment in the 2 study groups. Women who underwent episiotomy demonstrated a significantly worse performance, both for digital test and vaginal manometry, but not for the urine stream interruption test.
Perineal muscle function after childbirth has been poorly studied. Most studies address their attention to the consequences of perineal trauma (urinary and anal incontinence, urogenital prolapse), but there are few studies that focus on pelvic floor muscle assessment. We already know that midline episiotomy does not protect against urinary incontinence1,2 and genital prolapse,1 but we did not have a similar body of evidence about mediolateral episiotomy. Our results seem to confirm the same outcome for mediolateral episiotomy.
Pelvic floor muscle assessment after vaginal delivery is not well studied in the international literature, and we often find low numbers of women recruited. Peschers et al14 studied levator ani function in 55 women before and after childbirth and concluded that pelvic floor muscle strength is impaired shortly after vaginal birth, but for most women, this returns within 2 months, even if intravaginal pressure on perineometry remained significantly lower in primiparae. Gordon and Logue15 first measured perineal muscle function by means of a perineometer 1 year after childbirth and found no correlation between the degree of perineal trauma and subsequent muscle function. This is an important study because the authors concluded that perineal damage has little influence on muscle function, even if their data were obtained from only a few cases. We obtained similar results in a previous study,10 in which we demonstrated that only third- and fourth-degree perineal lacerations are associated with a higher incidence of anal incontinence (episiotomy was considered an exclusionary criterion), but we did not find a difference among the groups with regard to pelvic floor muscle strength. In the actual study, we purposely excluded third- and fourth-degree perineal lacerations because we wanted to evaluate the incidence of anal incontinence in our population after eliminating the major risk factor for it. We could criticize the decision of Gordon and Logue to perform an evaluation of pelvic floor muscle 1 year after vaginal delivery because perineal trauma is already consolidated, theoretically reducing the positive influence of a rehabilitation program. Röckner et al3 studied the effect of mediolateral episiotomy on pelvic floor strength evaluated only with vaginal cones in 87 women. The authors found that pelvic floor muscle strength was weakest in the episiotomy group, and these results are similar to ours, even if obtained with different methods of evaluation. Our study demonstrated that vaginal manometry and digital test presented significantly lower values in the episiotomy group than in the nonepisiotomy group, but the urine stream interruption test score did not. This difference could be due to the fact that the urine stream interruption test reflects only the activity of fast twitch fibers of levator ani, but not pelvic floor strength in toto.
Klein et al16 found that perineal and pelvic floor morbidity was greatest among women receiving median episiotomy compared with those remaining intact or sustaining spontaneous perineal tears. Episiotomy was associated with the weakest pelvic floor musculature, which was evaluated 3 months after delivery by electromyographic perineometry. These results are similar to ours, but the analysis was conducted on median episiotomy. Moreover, spontaneous perineal lacerations were less painful than episiotomy, and this is consistent with our findings. With regard to dyspareunia, Signorello et al9 found that 41% of primiparous women reported pain with sexual activity 3 months postpartum, but episiotomy was not considered.
Among the demographics and characteristics for each group, it is interesting to note that we found a significantly higher use of epidural analgesia in women who had an episiotomy. Can it be considered a confounding factor? Recently, our group published an interesting case-control study to determine the rate of anal and urinary incontinence and the pelvic floor function in women who underwent epidural analgesia.17 The conclusions were that the use of epidural analgesia is not associated with different rates of symptoms related to perineal trauma and pelvic floor weakness. The populations of that study and the actual study are very similar (primiparous women who underwent the same urogynecologic evaluation 3 months postpartum); on the basis of these data we do not think that the higher rate of epidurals in the episiotomy group affected the results significantly.
In conclusion, we found that mediolateral episiotomy does not protect against urinary and anal incontinence and vaginal prolapse and is associated with a significantly lower pelvic floor muscle strength than spontaneous perineal lacerations and with more dyspareunia and perineal pain.
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