McColgin 1990a.

Methods	A prospective randomised controlled trial.
Participants	Setting: USA Duration of study: not stated. Participants randomised: N = 103. Inclusion criteria: women at term (38 to 42 weeks' gestation) with gestational age ascertained by menstrual dates, early examination, and sonography before 20 weeks. Women with closed cervix were included (Page 811). Exclusion criteria: uncertain dates, abnormal fetal presentations, known medical complications of pregnancy, low lying placenta, placenta praevia, scheduled repeat caesarean section, or no desire to participate (Page 811). Parity: mixed. Both nulliparous and multiparous women included. No further data given. Bishop Score: unfavourable Bishop score (≤ 5) recorded.
Interventions	Membrane stripping (n = 51): weekly stripping of the membranes “digital separation from the lower uterine segment with 1 or 2 circumferential passes. Normally 1‐2cm of the membranes was separated from the lower uterine segment.” “In patients with long closed cervices”… “the cervix was digitally “stretched” until membrane stripping could be accomplished” (Page 811). Control group (n = 48): “weekly pelvic examination without membrane stripping” to assess cervix for Bishop scoring. All patients were examined every week in the same manner until admitted to labour/delivery ward or advanced beyond 42 weeks completed gestation. Two of the authors (SWM and JCU) performed almost all the membrane stripping and assignment of Bishops score (> 98%) (Page 811).
Outcomes	Caesarean section Forceps of vacuum Spontaneous vaginal delivery Chorioamnionitis Augmentation Oxytocin post SROM (induction of labour) Delivery within 1 week
Notes	Funding: none declared Trial authors’ declaration of interest: Department of Obstetrics and Gynaecology, United States Airforce Hospital, Tyndall Air Force base, Florida, USA. Department of Obstetrics and Gynaecology, University of Mississippi Medical Center, Jackson, Mississippi, USA (page 811). Informed consent obtained: yes “and obtaining informed consent” (page 811) Ethical approval: not stated. Unable to contact Dr McColgin
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	“we prospectively assigned patients at term (38‐42 weeks’ gestation)”, page 811. Unable to contact authors.
Allocation concealment (selection bias)	Unclear risk	Not reported. Method of randomisation not described Not stated if sealed, opaque envelopes used/or other method of allocation concealment. Unable to contact author.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Paticipants: not reported. Unable to contact author. Personnel: not blinded. “two authors (SWM and JCM performed almost all the membrane striping and assignment of Bishop’s score (> 98%).”, page 812.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported if person collecting the data was blinded to the interventions. Unable to contact author.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No evidence of attrition bias. 4 exclusions (2 patients in non‐stripped arm received stripping, 1 with pre‐eclampsia and 1 with breech presentation). N = 99 (103‐4) < 20%.
Selective reporting (reporting bias)	High risk	Data for age, parity, Bishop scores and gestational age were recorded but are not reported in study, page 812. Maternal and neonatal complications stated as trial outcomes but not reported in data.
Other bias	Low risk	No evidence of other bias