Sweeping ('stripping') of the membranes has the potential to initiate labour by increasing local production of prostaglandins and, thus, to reduce pregnancy duration or to pre-empt formal induction of labour with either oxytocin, prostaglandins or amniotomy. A Cochrane systematic review of 22 trials (2797 women) comparing membrane sweeping with no treatment, with prostaglandins and with oxytocin revealed that stripping of the membranes was associated with reduced frequency of pregnancy continuing beyond 41 and 42 weeks. To avoid formal induction of labour in one instance, membrane sweeping must be performed in 8 women. Discomfort during vaginal examination and other adverse effects (bleeding, irregular contractions) were reported more frequently by women allocated to sweeping. When used as a means of inducing labour, the reduction in the use of more formal methods of induction must be balanced against the resulting discomfort and other adverse effects.