McColgin 1990b.

Methods	Randomised controlled trial.
Participants	Setting: University of Mississippi Medical Center, Jackson, Mississippi, USA. Duration of study: enrolment = March 1998 to June 1999 (Page 679). Participants randomised: N = 209. Inclusion criteria: 38 weeks' gestation. “Gestational age was ascertained by uterine size and by ultrasound before 20 weeks' gestation with no size dates discrepancy.” (Page 678). Exclusion criteria: uncertain gestational dating criteria, nonvertex presentation, a known medical complication of pregnancy, vaginal or cervical infection. Placenta praevia, low lying placenta (Page 678). Exclusions after randomisation (29 women). Past history of caesarean section (17) in both groups. In the stripping group, 5 women were excluded for various reasons (abnormal presentation (2), dates unclear (1), pain (1), breast cancer (1)). In the control group, 7 women were excluded for various reasons (labour induction for maternal fetal indications (3), non vertex (1), dates (1), inadvertent stripping (1), renal disease (1)) (Page 679). Parity: mixed. Both nulliparous and multiparous women included (Table 1 page 679). Bishop score: initial Bishop score recorded (Mean ± SEM). Weekly Bishop scores collected in study but data not provided.
Interventions	Membrane stripping (n = 90): “Stripping of the membranes was accomplished by digital separation of 2‐3cm of the membranes from the lower uterine segment using 2 circumferential passes of the examining finger. In patients with long and closed cervices, the cervix was “stretched” digitally until membrane stripping could be accomplished.” (Page 678). Control group (n = 90): “Pelvic examination was performed by atraumatic assessment of the cervix for Bishop scoring” (Page 678). Bishop score was recorded for all patients (Page 678). All patients were examined every week in the same manner until delivery/scheduled induction or advanced beyond 42 weeks completed gestation (≥ 294 days).
Outcomes	Maternal Infection Fetal death (double nuchal cord) Mode of delivery: data not reported
Notes	Funding: none declared Trial authors’ declaration of interest: none declared Informed consent obtained: “Informed consent was obtained” Ethical approval: not stated. Unable to contact Dr McColgin
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“assigned by computer randomisation”, page 678.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants: not stated. Personnel: “two authors (S.W.M. and J.C.M. performed almost all the membrane striping and assignment of Bishop’s score (>98%).” No further information on blinding of personnel given, page 679.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated if person collecting the data was blinded to the interventions, therefore, insufficient information to inform judgement.
Incomplete outcome data (attrition bias) All outcomes	High risk	Of the 209 women initially recruited, 29 were excluded in total (< 20%). Although VBAC (vaginal birth after caesarean section) or history of a caesarean section were not listed in the exclusion criteria, 17 women with a history of caesarean section wanting a VBAC were excluded “when it became apparent that caesarean deliveries and post term pregnancies were unfairly biased against the control group in this select population” page 679
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting bias
Other bias	Low risk	No evidence of other bias.