Prospective comparative trial to define the optimum time for insemination during stimulated intrauterine insemination cycles

Objectives: To determine the clinical pregnancy rate (CPR) of women who underwent clomiphene citrate (CC) and human menopausal gonadotropin ovarian stimulation (OS) followed by intrauterine insemination (IUI) at varied times after hCG ovulation triggering and to determine the appropriate IUI timing.  Patients and Methods: 152 women with primary infertility secondary to male subfertility were randomly allocated into groups (I-IV) according to timing of IUI at 34-35, 35-36, 36-37, and 37-38hr after ovulation triggering. OS consisted of 5-days oral CC 100 mg once daily since day-3 of the menstrual cycle followed by daily injection of human menopausal gonadotropin 150 IU since day-8 until hCG injection. Ovulation was monitored using TVU for evident ovulation with a dominant follicle size >18 mm. IUI was repeated for three cycles and women were evaluated for clinical pregnancy rate (CPR) and abortion and multiple pregnancy rates were recorded.
Results: 44 women had clinical pregnancy for a total CPR of 28.9%. CPR% /patient was 15.8%, 34.2%, 42.1% and 23.7% and CPR%/cycle was 6, 14, 20 and 11 in the four groups, respectively with significant differences in favor of group III. Three women had ectopic and six women had multiple pregnancy and five women had abortion. Statistical analyses defined high number of performed IUI cycles as significantly negative, while longer time till IUI after hCG injection as significantly positive predictor for trial success. Kaplan-Meier regression analysis defined 37 hr (95% CI: 36.5-37.5) after hCG injection as the appropriate time to get the best chance for IUI success.  Conclusion: IUI after CC + GN ovarian stimulation is an appropriate policy for infertile couples secondary to male subfertility. Total motile sperm count threshold at ≥5 million gives acceptable outcome. Semen injection at 37 hr after hCG ovulation triggering gives the highest CPR.