Thomas S, et al. - Researchers conducted a randomized controlled trial comparing spontaneous ovulation monitored by urinary luteinizing hormone (LH) vs induced ovulation by the administration of human chorionic gonadotrophin (hCG) in terms of efficacy in couples undergoing gonadotrophin-stimulated intrauterine insemination (IUI). They randomized 392 couples with unexplained infertility, mild endometriosis, mild male factor infertility and polycystic ovarian syndrome to an LH group (Group A), in which urinary LH was measured daily to detect spontaneous ovulation, or an hCG group (Group B), in which urinary hCG was administered as a trigger. Outcomes revealed no significant disparity in clinical pregnancy rates when comparing urinary LH and hCG trigger as approaches to time insemination in women undergoing gonadotropin-stimulated IUI.