To establish the usefulness of a new drug regimen in an assisted conception program, a trial was performed comparing clomiphene citrate (CC) plus human menopausal gonadotropins (hMG) with a new regimen of intranasal luteinizing hormone-releasing hormone (LH-RH) analog plus hMG. One hundred two patient cycles received treatment with CC and hMG and 118 patient cycles received treatment with LH-RH analog and hMG. Fifteen percent of cycles were canceled in the CC group and 8% in the analog group. Four percent of cycles in the CC group were canceled due to premature ovulation. The number of oocytes collected in the analog group was significantly higher than in the CC group (8.5 versus 5.5), as was the number of mature oocytes (3.5 versus 2.7). However, the percentage of mature oocytes was higher in the CC group (54.2% versus 42.3%). The number of embryos resulting from in vitro fertilization as well as the number of cleaving embryos were significantly higher in the analog group (5.2 versus 2.8 and 4.6 versus 2.3, respectively). The pregnancy rate in the analog group was significantly higher than in the CC group (30.6% versus 16.1%), as was the live birth rate (21% versus 8%). Early pregnancy loss was significantly higher in the CC group than in the analog group (35% versus 9%); and the serum level of LH on the day of human chorionic gonadotropin (hCG) administration was also significantly elevated in the CC group when compared with the analog group (8.1 versus 4.1).(ABSTRACT TRUNCATED AT 250 WORDS)