ORIGINAL ARTICLE Comparison of pelvic floor muscle strength in nulliparous women and those with normal vaginal delivery and cesarean section Poorandokht Afshari 1 & Fariba Dabagh 1 & Mina Iravani 1 & Parvin Abedi 1 Received: 8 August 2016 /Accepted: 7 December 2016 # The International Urogynecological Association 2016 Abstract Introduction and hypothesis Weakness of the pelvic floor is quite common among women, and may occur following child- birth. The aim of this study was to compare pelvic floor muscle strength in women of reproductive age who were nulliparous or who had a cesarean section or normal vaginal delivery. Methods In this cross-sectional study, 341 women including 96 nulliparous women, 73 women with a history of normal vaginal delivery with and without episiotomy, and 172 women with a history of elective or emergency cesarean section were recruited randomly from public health centers in Ahvaz, Iran. Data were collected using a sociodemographic questionnaire and a checklist was used to record weight, height, body mass index, and pelvic floor muscle strength. Pelvic floor muscle strength was measured with the woman in the lithotomy po- sition using a Peritron 9300 V perineometer. Data were ana- lyzed using one-way analysis of variance, the least significant difference test and the chi-squared test. Results The nulliparous women had the highest mean pelvic muscle strength (55.62 ± 15.86 cm H 2 O). Women who had vaginal delivery with episiotomy had the lowest pelvic muscle strength (32.71 ± 14 cm H 2 O). In nulliparous women pelvic floor muscle strength was higher than in women who had normal vaginal delivery with episiotomy (p < 0.001), but was not significantly different from that in women with normal vaginal delivery without episiotomy or in women with cesarean section (elective or emergency, p = 0.245). Conclusions Nulliparous women had the highest pelvic floor muscle strength and there was no significant difference in pelvic floor muscle strength between women with normal vaginal delivery and those with cesarean section. Keywords Normal vaginal delivery . Cesarean section . Nulliparous women . Pelvic floor muscle strength Introduction Pelvic floor disorders (PFDs) may occur following childbirth. It is estimated that the prevalence of PFDs in the United States is 24% [1]. A study of 240 Iranian women aged 35–54 years showed that 89% had at least one PFD [2]. Predisposing factors for PFDs are age, vaginal delivery and obesity [1, 3, 4]. PFDs have physical, emotional and financial consequences for pa- tients. It was estimated that more than 225,000 American wom- en with PFDs underwent reconstructive surgery in 1997 [5]. The scores on the Pelvic Floor Distress Inventory [6] and Body Image Scale [7] are significantly lower in women with PFDs than in women with a normal pelvic floor. Diez-Itza et al. [8] assessed pelvic organ support in 382 primigravida women 6 months after childbirth. Women with instrumental vaginal delivery were five times more likely to undergo an examination for pelvic organ prolapse (OR 5.52, 95% CI 1.79–17.30) than those who had a cesarean section, while women with spontaneous vaginal birth were three times more likely (OR 3.19, 95% CI 1.07–9.49). In another study, in 469 women with obstructed defecation syndrome, posterior pelvic floor dysfunction was assessed using dynamic 3D ultra- sonography [9]. Older women experienced more posterior pel- vic floor dysfunction, while there were no significant relation- ships between mode of delivery and parity and posterior pelvic floor dysfunction. Chen et al. studied 110 nulliparous women * Parvin Abedi parvinabedi@ymail.com 1 Reproductive Health Promotion Research Center, Ahvaz Jundishapur University of Medical Sciences, 13th East Kianpars Ave, 1st Eastern Maroon, No:46, Ahvaz, Iran Int Urogynecol J DOI 10.1007/s00192-016-3239-6