Vaginal palpation versus transabdominal ultrasound in the comprehension of pelvic floor muscle contraction after vaginal delivery: a randomised controlled trial

Background Pelvic floor muscles support the pelvic organs and control voiding. The first choice in the repair of pelvic floor function that is damaged during pregnancy and delivery is pelvic floor muscle training, which involves repeated muscle relaxation and contraction. However, as muscle contractions cannot be visualised, it is difficult to assess whether patients understand how to contract them. Therefore, we assessed patients’ comprehension of pelvic floor muscle contraction by comparing two teaching methods, vaginal palpation and transabdominal ultrasound, following vaginal delivery. We hypothesised that vaginal palpation is better than transabdominal ultrasound in this regard. Methods This randomised controlled trial conducted in facilities in Tokyo, Japan between July 2018 and January 2019 included women aged ≥ 20 years at 4–6 weeks after vaginal delivery. The randomisation involved website-based centralised allocation. The primary outcome was a change in bladder base displacement during pelvic floor muscle contraction before and after training, which was measured using transabdominal ultrasound. Participants performed three contractions for 3 s, and the mean value was used for statistical analysis. The secondary outcome was a change in understanding the contraction before and after training, which was measured using a five-point Likert scale questionnaire. Outcomes were analysed using Welch’s t-test. Results Sixty-five participants were randomly allocated to the vaginal palpation group (n = 32) and transabdominal ultrasound group (n = 33). Baseline characteristics were similar between the groups. Changes in bladder base displacement were not significantly different between the groups (p = 0.181). Within-group analyses showed that bladder base displacement was large in both groups after the respective intervention. There were no significant differences in any of the outcomes between the two groups before and after the intervention. Conclusions Vaginal palpation and transabdominal ultrasound might be useful for comprehending pelvic floor muscle contraction after vaginal delivery. Trial registration: UMIN 000032304. Registered 18 April 2018, https://upload.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000036820.