Misoprostol prior to inserting an intrauterine device in nulligravidas: a randomized clinical trial.

STUDY QUESTION How effective is the vaginal administration of misoprostol in dilating the cervix prior to inserting an intrauterine device (IUD) in nulligravidas? SUMMARY ANSWER The use of misoprostol at a dose of 400 µg administered vaginally 4 h prior to IUD insertion increased the ease of insertion and reduced the incidence of pain during the procedure, although the frequency of cramps increased following misoprostol use. WHAT IS KNOWN AND WHAT THIS PAPER ADDS Misoprostol has been widely used in Obstetrics and Gynecology; however, its usefulness and efficacy in facilitating IUD insertion in nulligravidas have yet to be established. The present study shows that the benefits of misoprostol use prior to IUD insertion include facilitating insertion and reducing pain during the procedure; therefore, weighing up the benefits encountered against the only negative side effect (cramps prior to insertion), these results suggest that misoprostol use should become standard practice to facilitate IUD insertion in nulligravidas. STUDY DESIGN, SIZE DURATION A randomized, double-blind clinical trial was conducted. PARTICIPANTS/MATERIALS, SETTING METHODS Nulligravid women of reproductive age were submitted to IUD insertion between July 2009 and November 2011 at the Instituto de Medicina Integral Prof. Fernando Figueira in Recife, Pernambuco, Brazil. A total of 179 women were randomly allocated to two groups: 86 to receive 400 µg of misoprostol vaginally 4 h prior to IUD insertion and 93 to receive placebo. Risk ratios (RRs) were calculated as measures of relative risk, together with their 95% confidence intervals (95% CI). The number needed to treat (NNT) and the number needed to harm (NNH) were also calculated. MAIN RESULTS AND THE ROLE OF CHANCE Significant differences were found between the groups for all the immediate end points studied, with less difficulty in inserting the IUD [RR = 0.49 (23/86 versus 51/93); 95% CI: 0.33-0.72; P = 0.00005], a lower risk of dilatation <4 mm [RR = 0.48 (24/86 versus 54/93); 95% CI: 0.33-0.70; P = 0.0001], a reduction in moderate-to-severe pain at IUD insertion [RR = 0.56 (32/86 versus 62/93]; 95% CI: 0.41-0.76; P = 0.00008), as well as a lesser likelihood of experiencing a disagreeable or very disagreeable sensation [RR = 0.49(29/86 versus 64/93); 95% CI: 0.35-0.68; P = 0.000004] in the group that was given misoprostol compared with the group that received placebo. There was no significant difference between the groups in relation to complications during IUD insertion. There were no cases of uterine perforation in either group. The frequency of cramps was 40% higher in the misoprostol group. LIMITATIONS, REASONS FOR CAUTION The present study showed a positive balance between the benefits and risks of the use of misoprostol; however, it is not feasible to conclude that its use is imperative prior to IUD insertion in nulligravidas and IUD insertion should not be canceled when the medication is unavailable. WINDER IMPLICATIONS OF THE FINDINGS In view of its effect in promoting cervical dilatation, misoprostol may be used prior to IUD insertion both in nulligravidas and in any women with cervical stenosis irrespective of parity. STUDY FUNDING This study was funded by the Instituto de Medicina Integral Prof Fernando Figueira. COMPETING INTERESTS None.