The effect of luteal-phase support with vaginal progesterone on pregnancy rates in gonadotropin and clomiphene citrate/intra-uterine insemination cycles in unexplained infertility: A prospective randomised study

The purpose of this study is to analyse the effect of luteal-phase support on pregnancy rates in gonadotropin+intra-uterine insemination (Gn/IUI) and clomiphene citrate (CC)+IUI (CC/IUI) cycles in patients with unexplained infertility. Equal numbers of patients were recruited in two treatment arms (CC/IUI and Gn/IUI) (n=100, n=100, respectively). In each group, 50 patients received vaginal progesterone for 14 days (Crinone 8% vaginal gel, 90mg per day) for luteal-phase support from the day after IUI and continued until menstruation or the 10th week of gestation if pregnant. There were 29 clinical pregnancies among 200 patients. Pregnancy rates were 12% in CC/IUI cycles, 10% in luteal-phase-supported CC/IUI cycles 16% in Gn/IUI cycles and 20% in luteal-phase-supported Gn/IUI cycles. Although pregnancy rates were higher in Gn/IUI cycles compared to CC/IUI cycles, luteal-phase support did not significantly affect the pregnancy rates in both groups. This study implies that luteal-phase support with progesterone has no pronounced beneficial effect on pregnancy rates in either CC/IUI or Gn/IUI cycles in patients with unexplained infertility.