Study	Reason for exclusion
Bergsjo 1989	Randomised comparison of sweeping of membranes and oxytocin (94 women) versus expectant management with surveillance (94 women) in women with post‐term pregnancy (at or beyond 42 weeks of gestation).
Foong 2000	Sweeping of membranes was evaluated as an addition to oxytocin, amniotomy or prostaglandins. Method of concealment of the allocation is unclear. The results of this study suggested that sweeping of membranes during the induction of labour process reduces the risk of caesarean section (8/124 versus 17/124, p = 0.06). This effect was more apparent in nulliparous women who had cervical ripening with prostaglandins (unfavourable cervix) (3/48 versus 12/55, p = 0.01).
Gemer 2001	50 women were randomised (based on hospital number) to sweeping of membranes or PGE2 0.5 mg intracervical gel. Change in Bishop score was evaluated (1 assessor), but no other outcomes are reported. The study was excluded based on an inadequate method of concealment of the allocation.
McColgin 1993	Randomized study, comparing microbiological, histological and biochemical markers of onset of labour in 30 women allocated to 3 groups (sweeping, Bishop score and no vaginal examination, 10 in each group). No clinical outcomes reported.
Swann 1958	Method of allocation: women had to be allocated to one of the following groups: (1) stripping; (2) insertion of the finger in the cervix; (3) vaginal examination. One in every three women had to be allocated in turn to each group. Despite this schedule (not concealed to the resident in charge) that would have produced balanced groups, 147 women were allocated to membrane stripping, 29 to 'finger control' and 45 to 'Bishop score only'. This major imbalance, together with the inadequate method of randomisation, raises the suspicion of a selection bias. In addition, outcome measures were poorly defined and results difficult to interpret.