A multicenter randomised controlled trial assessing the effectiveness of immobilisation versus immediate mobilisation after intra-uterine insemination (ISRCTN53294431).

IM Custers^a, P Flierman^b, P Maas^g , T Cox^c, HJHM Van Dessel^d, MH Gerards^f, MH Mochtar^a, CAH Janssen^e, F van der Veen^a, BWJ Mol^a

^aCentre for Reproductive Medicine, Academic Medical Centre, Amsterdam, The Netherlands

^bOnze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands, ^c Antonius Ziekenhuis, Nieuwegein, The Netherlands, ^d TweeSteden Ziekenhuis, Tilburg, The Netherlands, ^e Groene Hart Ziekenhuis, Gouda, The Netherlands, ^fMartini Ziekenhuis, Groningen, The Netherlands and ^gMáxima Medical Centre, Veldhoven, The Netherlands

Introduction Intra uterine insemination (IUI) is a commonly used treatment for couples with male, cervical and unexplained subfertility. One of the unresolved issues in the use of IUI is, whether the patient can be mobilized immediately after IUI, or that she should stay in supine position for a short period of time. Studies on sperm migration and survival in the female genital tract suggest that sperm migration to the site of fertilization is independent of the position of the woman directly after IUI. However one small randomised clinical trial on the subject indicated benefit of immobilisation. We therefore evaluated the effectiveness of 15 minutes of immobilisation versus immediate mobilization after IUI.

Methods We studied couples with unexplained, cervical factor or male subfertility with an indication for IUI. The women were randomly assigned to immediate mobilization or 15 minutes of immobilization following insemination. The study had a parallel design for three consecutive treatment cycles within a time-horizon of 4 months. The primary endpoint was ongoing pregnancy. Analysis was done by intention to treat. Anticipating a difference of 4% per cycle to be relevant (12% per couple after 3 three cycles), we needed 185 couples per arm (one-sided test, alpha-error of 0.05, beta-error of 0.20).

Results Of the couples enrolled in the study, 191 were assigned to “mobilization” and 198 were assigned to “immobilization”. At present we have completed 92% of the follow-up. The baseline characteristics of the two groups were comparable. The number of ongoing pregnancies in the “mobilization” group was 23 (12% per couple), versus 42 (21% per couple) in the “immobilization” group (RR 1.8, CI 1.1 to 2.8, p 0.02). The clinical and ongoing pregnancy rates per cycle were 5.0% and 8.2% for the “mobilization” group, and 9.2% and 11.6% per cycle in the “immobilization” group.