Gonadotrophin-releasing hormone agonist compared with human chorionic gonadotrophin for ovulation induction after clomiphene citrate treatment

The objective of this study was to compare hormonal response, luteal phase adequacy and pregnancy and abortion rates in patients randomized to receive human chorionic gonadotrophin (HCG) or gonadotrophinreleasing hormone agonist (GnRHa) during ovulation cycles stimulated by clomiphene citrate. Anovulatory patients received either one s.c. dose of tryptorelin (0.1 mg; n = 104) or one i.m. dose of HCG (10 000 IU; n = 106) after clomiphene citrate stimulation had induced enlarged ovarian follicles (>17 mm in diameter). A short-lived, transitory increase in serum luteinizing hormone (98 ± 9 IU/1) and follicle-stimulating hormone (30 ± 5 IU/1) concentrations was measured at 12 h following the injection of GnRHa, and these concentrations returned to baseline levels by 36 h post-injection. Midluteal progesterone concentrations were similar in both groups (>10 ng/ml), and the mean luteal phase duration was also not significantly different (13 days). There were no significant differences in the mean number of pregnancies (12.0 versus 12.6% per cycle) and the abortion rate (18.2 versus 12.5%) between the GnRHa- and HCG-treated groups respectively. There were no complications related to treatment in either group. The results show that a relatively low dose of GnRHa can be used in place of HCG to induce ovulation in clomiphene citrate-treated patients.