Clinical impact of LH rises prior to and during ganirelix treatment started on day 5 or on day 6 of ovarian stimulation

BACKGROUND: We sought to evaluate the incidence and clinical impact of luteinizing hormone (LH) rises prior to and during gonadotropin-releasing hormone (GnRH) antagonist treatment started on day 5 or 6 of ovarian stimulation with recombinant follicle-stimulating hormone (rFSH). METHODS: Pooled data from three trials with the GnRH antagonist ganirelix started on day 5 (n = 961) and from five trials with ganirelix started on day 6 (n = 1135) of ovarian stimulation with rFSH were retrospectively analyzed. RESULTS: The incidence of LH rises (LH ≥ 10.0 IU/L) prior to ganirelix treatment was 2.3% and 6.6% on ganirelix start days 5 and 6, respectively (P < 0.01). During ganirelix treatment this incidence was 1.2% and 2.3%, respectively (P = 0.06). Women with LH rise on day 5 or 6 had a higher ovarian response with more oocytes recovered, mean ± SD, 12.9 ± 8.5 versus no LH rise, 10.2 ± 6.4 (P < 0.01). In women with and without LH rise prior to ganirelix treatment the ongoing pregnancy rates were similar (26.0% vs 29.9%; odds ratio [OR], 0.89; 95% confidence interval [CI], 0.55-1.44). Women with LH rise during ganirelix treatment had a lower ovarian response with 7.5 ± 6.7 oocytes recovered versus no LH rise, 10.2 ± 6.4 (P = 0.02) and a tendancy for a lower chance of ongoing pregnancy (16.7% vs 29.9%; OR, 0.52; 95% CI, 0.21-1.26). CONCLUSIONS: The incidence of early and late LH rises was low but may be further reduced by initiating ganirelix on stimulation day 5 rather than on day 6. In contrast to women with an early LH rise, women with a late LH rise may have a reduced chance of ongoing pregnancy.