Berghella 1996.

Methods	Randomised controlled trial.
Participants	Setting: Chinatown Health Clinic affiliated with New York Downtown Hospital. New York, USA. Page 927 Duration of study: 1 July 1991 to 30 October 1991, when the first author was the sole obstetrical provider for the clinic, and from 1 July 1993 to 30 October 1993, when the second author was the sole obstetrical provider for the clinic. Page 927 Inclusion criteria: 38 weeks' gestation “all patients included in the study were low risk. Exact gestational age was verified either by a pelvic examination during the first 12 menstrual weeks to confirm size appropriate for dates, by an ultrasound examination before the 20th week, or both”. Page 927 Exclusion criteria: “Patients who presented after 20 weeks”, “multiple pregnancy, placenta previa, low‐lying placenta, non vertex presentation, fetal growth restriction, and any medical complication of pregnancy, such as hypertension and insulin‐dependent diabetes.” “Patients with long, closed cervices that did not allow stripping”. Page 927 Parity: mixed, both nulliparous and multiparous women included. (Table 1 Page 928) Bishop score: "Bishop scores were recorded for all patients." (Table 1 Page 928)
Interventions	Duration of study: 1 July 1991 to 30 October 1991, when the first author was the sole obstetrical provider for the clinic, and from 1 July 1993 to 30 October 1993, when the second author was the sole obstetrical provider for the clinic. Page 927 Setting: Chinatown Health Clinic affiliated with New York Downtown Hospital. New York, USA. Page 927 Membrane stripping: n = 73 weekly stripping of membranes starting at 38 weeks' gestational age. “Stripping of membranes was performed uniformly by both authors by separating an approximately 2 cm to 3 cm section of the lower membranes from its cervical attachment with at least two circumferential passes of the index finger.” Stripping was repeated weekly according to randomisation until delivery occurred. Page 928 Control group:n = 69 “Weekly gentle cervical examinations” “gentle cervical examinations were repeated weekly according to randomisation until delivery occurred.”Page 928 Bishop scores were recorded for all patients. Page 928
Outcomes	Spontaneous vaginal delivery: Vacuum Low forceps Primary caesarean section
Notes	Funding: none declared. Trial authors’ declaration of interest: none declared. Informed consent obtained: “signed informed Internal Review Board consent forms and were randomized” Page 927 Ethical approval: not stated Email sent to Dr Vincenzo Berghella requesting information for subgroup analysis. Sent 10 August 2017 and 28 August 2017 No reply to date.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“randomized using computer generated numbers from opaque, sealed envelopes.” Page 927
Allocation concealment (selection bias)	Unclear risk	Allocation concealment with “opaque, sealed envelopes.” Page 927. Not stated if numbered or sequential.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants: blinding of patients not reported. Personnel: clinicians not blinded “These time frames were chosen so that only one investigator would perform all the examinations in a given period.” Page 927
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding details given in study. “After all the patients had delivered, the data were analyzed for statistical differences using the two‐sample t test, the Mann‐Whitney test, the generalized Fisher exact test, or x2, as appropriate.” Page 928
Incomplete outcome data (attrition bias) All outcomes	Low risk	No evidence of attrition bias.It is noted that 7 patients “initially included in the study were excluded because of long closed cervices not amenable to stripping” page 928
Selective reporting (reporting bias)	Low risk	No evidence of selective reporting bias.
Other bias	High risk	There is disparity in the study numbers as shown in table 1 page 928: Control group (n = 69): Primiparous n = 43 multiparous n = 26 Sweep group (n = 73): Primiparous n = 35 multiparous n = 38 Also as stated in the study “the original Bishop scores of the two groups were not recorded and compared, so this small study could have been biased by dissimilar patient characteristics in the two groups.” Page 929