The authors examined the hypothesis that active ovulation management would increase the monthly probability of pregnancy occurrence (MPO) in ovulatory women who require intrauterine insemination (IUI). All patients were initially treated during spontaneous ovulatory cycles with IUI performed after the detection of an endogenous lutenizing hormone (LH) surge (phase 1). For phase 2, those patients who had not conceived were offered treatment with fertility medication and IUIs were scheduled accordingly. Four of 76 (5.3%) patients conceived during 180 treatment cycles in phase 1; 9 of 44 (20.5%) patients conceived during 105 treatment cycles in phase 2. The average MPO was 0.022 in phase 1, and 0.085 in phase 2: the difference is significant (P less than 0.02). The authors conclude that fertility medication improves MPO in ovulatory women who undergo IUI for certain infertility situations.