Dyson 1987.

Study characteristics
Methods	RCT
Participants	Number of women randomised: 302 Setting: Kaiser Permanente Medical Care Hospital in California, USA Study date: study conducted 11 January 1983 to 3 December 1985 Inclusion criteria Well‐established GA of at least 287 days GA at intervention: at least 41 completed weeks (287 days) Parity: ~70% nulliparous Exclusion criteria Non‐reactive NST result Variable decelerations on NST Oligohydramnios Any risk factors known to increase perinatal death and morbidity rates (such as chronic hypertension, pre‐eclampsia, diabetes mellitus, growth restriction and previous stillbirth) Any risk factors known to increase the risk of induction, such as multiple gestation and polyhydramnios Any risk factors known to markedly increase the caesarean section rate, such as breech presentation and previous caesarean section Cervical score of > 6 State of cervix: unfavourable (Bishop score < 6)
Interventions	Induction group (n = 152): PE2 gel (initially 3 mg but later reduced to 0.5 mg). If no labour in 24 hours, repeat PE2 and oxytocin if needed versus EM group (n = 150): NST twice weekly, pelvic examination and amniotic fluid determination weekly between 41‐42 weeks and twice weekly afterwards
Outcomes	Mother: length of hospital stay; caesarean section; length of labour Baby: perinatal death; 1 minute Apgar score < 7; 5 minute Apgar score < 7; meconium‐stained amniotic fluid; meconium aspiration syndrome; post‐maturity syndrome; fetal distress; birthweight; birthweight > 4000 g; infant hospital stay length
Notes	Funding: Community Service Program of Kaiser Foundation Hospitals Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A table of random numbers was used.
Allocation concealment (selection bias)	Unclear risk	The authors reported " using a series of consecutively numbered, sealed envelopes..." for allocation concealment, but no mention was made of envelope opaqueness.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding was not feasible.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinded outcome assessment was not mentioned.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses to follow‐up or exclusions
Selective reporting (reporting bias)	Unclear risk	No outcomes were prespecified in the methods; no access to trial protocol to further assess selective reporting
Other bias	Low risk	Appeared to be free of other bias