Immobilization or mobilization after IUI: an RCT

Does 15 min of immobilization after IUI improve pregnancy rates?Immobilization for 15 min after IUI does not improve pregnancy rates.Prior RCTs report a beneficial effect of supine immobilization for 15 min following IUI compared to immediate mobilization, however, these studies can be criticized. Given the importance for the logistics in daily practice and the lack of biological plausibility we planned a replication study prior to potential implementation of this procedure.A single centre RCT, based in an academic setting in the Netherlands, was performed. Participants were randomly assigned for 15 min of supine immobilization following IUI for a maximum of six cycles compared to the standard procedure of immediate mobilization following IUI. Participants and caregivers were not blinded to group assignment. An independent researcher used computer-generated tables to allocate treatments. Stratification occurred to the indication of IUI (unexplained or mild male subfertility). Revelation of allocation took place just before the insemination by the caregiver. The primary outcome was ongoing pregnancy rate per couple.A total of 498 couples diagnosed with unexplained or mild male subfertility and an indication for treatment with IUI were approached and randomized in the study, of which 244 participants were assigned to 15 min of supine immobilization and 254 participants to immediate mobilization.Participant characteristics were comparable between the groups, and 236 participants were analysed in the immobilization group, versus 245 in the mobilization group. The ongoing pregnancy rate per couple was not found to be superior in the immobilization group (one-sided P-value = 0.97) with 76/236 ongoing pregnancies (32.2%) being accomplished in the immobilization and 98/245 ongoing pregnancies (40.0%) in the immediate mobilization group (relative risk 0.81; 95% CI [0.63, 1.02], risk difference: -7.8%, 95% CI [-16.4%, 0.8%]). No difference was found in miscarriage rate, multiple gestation rate, live birth rate and time to pregnancy between the groups.Owing to discontinuation of the planned treatment not all participants reached six IUI cycles or an ongoing pregnancy. However, this is as expected in IUI treatment and mirrors clinical practice. These participants were equally distributed across the two groups. Women with tubal pathology and endocrine disorders were excluded for this trial, and this might narrow generalizability.This study shows no positive effect of 15 min of immobilization following IUI on pregnancy rates. Based on available evidence today, including our study, a possible beneficial effect of supine immobilization after IUI is at least doubtful and straightforward implementation does not seem to be justified.No funding was received. All authors have nothing to disclose.Dutch Trial Register NTR 2418.20 July 2010.11 August 2010.