Crane 1997.

Methods	Randomised controlled trial
Participants	Setting: Grace General Hospital, Newfoundland, Canada. Duration of study: 18 months Inclusion criteria: “low risk (as defined by the Newfoundland antenatal form), at 38‐40 completed weeks ‘gestation based on firm dates (last menstrual period) or early ultrasound (at or before 18 weeks‘ gestation).” Written informed consent. Page 586 Exclusion criteria: exclusion criteria included important medical diseases, pregnancy complications (including bleeding, hypertension, or preterm labour), evidence of fetal growth restriction, history of perinatal mortality or low birthweight infant, uncertain dating, premature rupture of membranes (PROM), abnormal presentation, placenta previa, scheduled caesarean delivery, or any other contraindication to vaginal delivery. Page 586 Parity: mixed, both nulliparous and multiparous women included (% presented in Table 1 of manuscript page 587). Bishop Score: Bishop scores were recorded for all patients (% presented in Figure 1 of manuscript page 587).
Interventions	“The groups were stratified based on the status of the cervix at pelvic examination (opened versus closed), with randomization within the strata.” Page 586 Membrane stripping (n = 76): “after the status of the cervix was determined (i.e. whether it admitted a fingertip through the internal OS). Those assigned to the sweeping‐membranes group underwent sweeping, whereby as much membrane as possible was separated from the lower uterine segment by sweeping the examiner’s index finger twice in a circumferential manner. If the examiner was unable to pass a fingertip through the cervix, vigorous cervical massage was performed, defined as firmly rubbing the external OS in a circular manner with the examining index finger.”Page 587 Control group (n = 74): “the control group had an internal examination only.” Page 587
Outcomes	Spontaneous onset labour Induction Mode of birth Spontaneous Forceps/vacuum Caesarean Analgesia in labour: Epidural Apgar score < 7 at 5 minutes Neonatal infection
Notes	Funding: none declared Trial authors’ declaration of interest: none declared Informed consent obtained: “consent for enrolment was sought. Written informed consent was obtained from all subjects” Ethical approval: “the study was approved by the Human Investigation Committee of Memorial University of Newfoundland as well as the hospital.” Email sent requesting further information: Email received 8 September 2017 "With regards to our study, participants and personnel were not blinded. Outcome assessment was not blinded. We no longer have the original data file for this study. At the time the study was completed and published (1997) out ethics board required retention of research data for 10 years. We have since moved to a new site and in this move some research files older than 10 years were destroyed."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“random‐number tables by blocks of six, using opaque, sealed, sequentially numbered envelopes. The groups were stratified based on the status of the cervix at pelvic examination (opened versus closed), with randomization within the strata.". Page 586
Allocation concealment (selection bias)	Low risk	“random‐number tables by blocks of six, using opaque, sealed, sequentially numbered envelopes." “The envelope was opened by the attending nurse during the internal examination by an investigator, after the status of the cervix was determined”. Page 586
Blinding of participants and personnel (performance bias) All outcomes	High risk	Personnel: not blinded. “The envelope was opened by the attending nurse during the internal examination by an investigator, after the status of the cervix was determined” But clinicians aware of group allocation prior to intervention/no intervention. Page 586 Participants: not blinded. This bias was confirmed by Dr. Crane on 8 September 2017 in an email stating, “participants and personnel were not blinded. Outcome assessment was not blinded.”
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome assessment was not blinded “Medical records were reviewed after delivery to record these variables.” This bias was confirmed by Dr. Crane on 8 September 2017 in an email stating, “participants and personnel were not blinded. Outcome assessment was not blinded.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	No evidence of attrition bias.
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting bias noted.
Other bias	Low risk	No evidence of other bias. Protocol not available