Pelvic floor muscle strength and thickness in continent and incontinent nulliparous pregnant women

The aim of the study was to measure pelvic floor muscle function in continent and incontinent nulliparous pregnant women. The study group consisted of 103 nulliparous pregnant women at 20 weeks of pregnancy. Women reporting urinary incontinence once per week or more during the previous month were classified as incontinent. Function was measured by vaginal squeeze pressure (muscle strength) and increment in thickness of the superficial pelvic floor muscles (urogenital diaphragm) assessed by perineal ultrasound. Seventy-one women were classified as continent and 32 women as incontinent. Continent women had statistically significantly higher maximal vaginal squeeze pressure and increment in muscle thickness when compared with incontinent women. There was a strong correlation between measurements of vaginal squeeze pressure and perineal ultrasound measurements of increment in muscle thickness. This study demonstrates statistically significant differences in pelvic floor muscle function measured by strength and thickness in continent compared with incontinent nulliparous pregnant women. Editorial Comment: This study evaluated pelvic floor muscle function in 103 nulliparous continent and incontinent women at 18–20 weeks gestation. Pelvic floor muscle strength was assessed by measuring vaginal squeeze pressure, and thickness of the urogenital diaphragm during both relaxation and contraction was measured using perineal ultrasound. The authors found a statistically significant higher vaginal squeeze pressure and higher mean increment in muscle thickness in the continent compared with incontinent group as well as a strong correlation between pelvic floor muscle strength and increment in thickness. Although describing several benefits of ultrasonography in assessing pelvic floor muscles, the authors did acknowledge the difficulty in identifying and measuring these muscles, and the learning curve involved with perineal ultrasound. Another limitation was the subjective classification of continence status based on self-reported symptoms. The implication of low pelvic floor muscle strength and thickness as risk factors for the development of urinary incontinence is beyond the scope of this study.