The changes in urogenital organ morphology or tomography might have a clinical effect on the subsequent development of pelvic organ prolapse and urinary incontinence. It has been established that levator ani muscle avulsion increases the risk of pelvic organ prolapse. [1] Levator ani muscle avulsion from vaginal birth resulting in decreased pelvic floor muscle strength, vaginal hiatal enlargement and pelvic organ prolapse. [2] Vaginal birth is the strongest risk for developing pelvic organ prolapse and the prevalence of levator injury was reported approximately 13-36%. [3] The severity of sphincter tear and vaginal laceration were found to be independent clinical predictors of increased risk of levator ani muscle avulsion. To prevent pelvic organ prolapse following vaginal delivery, a reduced degree of perineal laceration may be the potential role. Therefore, we conducted the study to compare levator ani muscle avulsion following vaginal birth with routine versus restrictive episiotomy.

The prospective observational study recruited postpartum primiparas women with normal vaginal delivery at a tertiary hospital between February and December 2016. Deliveries were classified as routine or restrictive episiotomy. Inclusion criteria include postpartum primiparas women with vaginal delivery at 6-12 weeks postpartum periods, age over 18 years and no pelvic surgery for prolapse or pelvic trauma before. Exclusion criteria include postpartum primiparas women who were delivered vaginally with preterm baby, non-cephalic presentation, twin delivery or instrumental delivery.

Sixty-one post-partum women participated in our study. Thirty-two women (52.5%) have undergone routine episiotomy. While twenty-nine (47.5%) have been performed restrictive episiotomy. The mean age + SD of routine and restrictive episiotomy were 24.8 + 4.5 and 25.0 + 5.3 years, respectively. The mean BMI + SD of routine was 21.3 + 2.3 kg/m2 and restrictive episiotomy was 22.4 + 3.4 kg/m2. There were no statistical differences in age and BMI between two groups. (p= 0.89 and p= 0.13, respectively). Right mediolateral episiotomy was performed in all cases. The rate of anal sphincter tear after routine episiotomy was detected 12.5% and restrictive episiotomy was 13.8% (p=1.00). 
Regarding the baby weight and baby head circumference, there were no statistical differences between two groups (p= 0.28 and p=0.68, respectively). No statistical differences in the duration of the first and second stages of labor between two groups (p=0.15 and p=0.72, respectively). No statistically significant differences of pelvic floor dysfunction symptoms such as stress urinary symptoms, overactive bladder symptoms, dragging sensation and vaginal laxity at 6-12 weeks after delivery.
Levator ani avulsion was detected only on right-sided after routine episiotomy (9.4%) and restrictive episiotomy (10.3%)(Figure1). No bilateral levator avulsion was found. There were no statistically significant differences regarding the incidence of avulsion between two groups (p=1.00). Regarding other pelvic floor parameters, there were no statistical differences of the bladder neck descent, cystocele descent, uterine descent, rectocele descent and the ballooning of the genital hiatus area as shown in Table1.

There were no differences in the rate of levator avulsion between routine and restrictive episiotomy. Moreover, the differences were not detected on other pelvic floor parameters.

The restrictive episiotomy did not reduce the rate of levator ani avulsion when comparing with the routine episiotomy. Moreover, this technique did not also improve the pelvic floor parameters.

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