Protocol Changes
SUI, pelvic floor muscle strength
VAGINA, SECONDARY, RECRUITMENT
We have made several modifications to the original protocol before trial onset. First, the inclusion criteria were changed to gain additional insight into the preventive effect of the UIW app–based intervention. Therefore, we included all pregnant women regardless of UI status and type of UI, instead of recruiting only pregnant women with stress UI (SUI), as planned at the study onset. In addition, the sample size estimation was changed accordingly. Second, the secondary outcomes were updated. We excluded the assessment of pelvic floor muscle strength (originally a secondary outcome) at 6 weeks post partum because of the poor acceptability of pelvic floor muscle surface electromyography among Chinese women at the time of recruitment, a measurement that requires the insertion of a vaginal probe into the vagina. We also replaced the risk factors for UI (originally a secondary outcome) with UI-related knowledge (supplementally a secondary outcome). In addition, after trial commencement, although we did our best to follow up as many participants as possible at 3 months and 6 months post partum (originally follow-up end points), the loss rate at 3 months post partum was higher than expected; therefore, outcomes were reported only at 2 months after randomization and 6 weeks post partum. The abovementioned changes were implemented before the data were processed, with no effect on trial implementation.