Gorbea 2004

Methods	2‐arm (parallel groups) RCT.
Participants	75 pregnant nulliparous women. Inclusion: aged 15‐35 years without stress UI at 20 weeks' gestation. Exclusion: multiple pregnancy, ≥ 2 caesarean births, oligohydramnios or polyhydramnios, cervical incompetence, maternal‐fetal iso‐immunisation, severe pregnancy‐induced hypertension, chronic degenerative conditions affecting pelvic floor function such as diabetes mellitus and multiple sclerosis. Age, mean (SD), years: PFMT 26 (6); 24 (7). Parity, mean (SD): PFMT 1.4 (0.8); control 1.4 (0.7). Delivery: PFMT 42.1% vaginal, 57.9% caesarean; control 64.7% vaginal, 35.3% caesarean Weight at 35 weeks' gestation, mean (SD), kg: PFMT 66 (7); control 66 (13). Incontinence at recruitment: none (see inclusion criteria). Setting: single‐centre, Mexico.
Interventions	PFMT (n = 38): taught by physiotherapist. 8 × 1‐hour visits over 8 weeks, then weekly telephone calls. Also received information about anatomy and physiology of lower urinary tract, and biofeedback from surface electromyography electrodes (either side of anus) at clinic visits. Control (n = 34): requested not to perform PFMT during pregnancy or postpartum.
Outcomes	Measured at 28 and 35 weeks' gestation, and 6 weeks' postpartum. Primary endpoint: 6 weeks' postpartum. Primary outcome: self‐reported UI. Secondary outcomes: frequency and severity of UI, cough test, PFM activity (electromyography).
Notes	Losses to follow‐up: 3/75 (total 4%); data not available by group. Funding: not reported. Conflicts of interest: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants names in sealed envelopes and assigned random numbers to divide them into 2 groups randomly.
Allocation concealment (selection bias)	Low risk	The sealed envelopes were held by the secretary who did not have any relationship to the study: she opened them and assigned the women to each group.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Unblinded reporting of UI self‐report outcomes because they were participant reported. Unclear if cough test and electromyography were blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	4% dropout; unclear if similar between groups; no reasons provided; no mention of imputation for missing data.
Selective reporting (reporting bias)	Low risk	Outcome measures described in methods were reported in results.
Other bias	Unclear risk	Significant difference between groups with respect to weight gain during pregnancy (greater in the PFMT group) and self‐reported UI at 28 weeks' gestation (more prevalent in the PFMT group).