A comparison of oral and vaginal misoprostol for induction of labour at term: a randomised trial

Objective To compare the efficacy of oral with vaginal misoprostol for indu ction of labour at term. Design Randomised trial. Setting Tertiary Care hospital. Participants One hundred and sixty-seven wo men requiring induction of labour. :Methods The women were randomised to re ceive 50 mug of misoprostol orally or vaginally every 6 h until the cen ix was favourable for amniotomy, spontaneous rupture of membranes, or active l abour occurred. Sample size was calculated with a two-tailed alpha of 0.05 and a power of 95% to detect a 5 h difference in induction-to-delivery time . Student's t test was used for comparison of normally distributed continuo us variables and the Mann-Whitney U test was used for non-Gaussian distribu ted continuous variables. Fisher's exact and chi (2) tests were used for co mparison of categorical variables. The main outcome measure was induction t o delivery time. Results The median induction to delivery time was significantly shorter wit h vaginal misoprostol (15.7 h range 4.3-55.7), compared with oral misoprost ol (23.0 h range 3.2-141.7, P = 0.0013). The median number of doses was als o significantly less in the vaginal misoprostol group, 1 (range 1-3), compa red with the oral group, 2 (range 1-8), (P < 0.0001). The significant diffe rences in outcome held true when nulliparous and multiparous women were ana lysed separately. There were no differences between the two routes of admin istration with respect to rates of hyperstimulation or neonatal asphyxia. T hen were more caesarean sections in the vaginal misoprostol group, but the difference was not statistically significant. Conclusions Compared with oral misoprostol, vaginal misoprostol for inducti on of labour at term results in a shorter induction-to-delivery time, with fewer doses required per patient. Vaginal misoprostol may be associated wit h higher rates of caesarean section than oral misoprostol.