title: Distensibility and strength of the pelvic floor muscles of women in the third trimester of pregnancy.
abstract: OBJECTIVE
  The objective of this study was to compare the role of the pelvic floor muscles between nulliparous and multiparous women in the third trimester of pregnancy, by analyzing the relationship between electrical activity (surface electromyography-EMG), vaginal palpation (modified Oxford scale), and perineal distensibility (Epi-no).
  
  
  METHODS
  This was an observational cross-sectional study on a sample of 60 healthy pregnant women with no cervical dilation, single fetus, gestational age between 35 and 40 weeks, and maternal age ranging from 15 to 40 years. The methods used were bidigital palpation (modified Oxford scale, graded 0-5), surface EMG (electrical activity during maximal voluntary contraction), and perineal distensibility (Epi-no device). The Pearson correlation coefficient (r) was used to analyze the Epi-no values and the surface EMG findings. The Kruskal-Wallis test was used to compare the median values from surface EMG and Epi-no, using the modified Oxford scale scores.
  
  
  RESULTS
  Among the 60 patients included in this study, 30 were nulliparous and 30 multiparous. The average maternal age and gestational age were 26.06 (± 5.58) and 36.56 (± 1.23), respectively. It was observed that nulliparous women had both higher perineal muscle strength (2.53 ± 0.57 versus 2.06 ± 0.64; P = 0.005) and higher electrical activity (45.35 ± 12.24 μV versus 35.79 ± 11.66 μV; P = 0.003), while among the multiparous women, distensibility was higher (19.39 ± 1.92 versus 18.05 ± 2.14; P = 0.013). We observed that there was no correlation between perineal distensibility and electrical activity during maximal voluntary contraction (r = - 0.193; P = 0.140). However, we found a positive relationship between vaginal palpation and surface electromyography (P = 0.008), but none between Epi-no values (P = 0.785).
  
  
  CONCLUSIONS
  The electrical activity and muscle strength of the pelvic floor muscles of the multiparous women were damaged, in relation to the nulliparous women, while the perineal distensibility was lower in the latter group. There was a positive relationship between surface EMG and the modified Oxford scale.
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Carla Dellabarba
authors.initials: CD
authors.lastname: Petricelli
authors.affiliation: Faculty of Physical Education and Physiotherapy, Federal University of Uberlândia (UFU), Uberlândia, MG, Brazil.
authors.forename: Ana Paula Magalhães
authors.initials: AP
authors.lastname: Resende
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Julio
authors.initials: J
authors.lastname: Elito Júnior
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Edward
authors.initials: E
authors.lastname: Araujo Júnior
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Sandra Maria
authors.initials: SM
authors.lastname: Alexandre
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Miriam Raquel Diniz
authors.initials: MR
authors.lastname: Zanetti
authors.affiliation: Department of Obstetrics, Federal University of São Paulo (UNIFESP), Rua Carlos Weber, 956 Apartment, 113 Visage, 05303-000 Vila Leopoldina, SP, Brazil.
authors.forename: Mary Uchiyama
authors.initials: MU
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005260:Female; D020073:Gravidity / Q000502:physiology*; D006801:Humans; D053580:Muscle Strength / Q000502:physiology*; D017773:Pelvic Floor / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D011263:Pregnancy Trimester, Third / Q000502:physiology*