GnRH antagonists in ovarian stimulation: a treatment regimen of clinicians’ second choice? Data from the German national IVF registry

Abstract

The place of GnRH antagonists in ovarian stimulation is controversial. Meta-analyses on studies comparing GnRH agonist and GnRH antagonist treatment regimens have suggested a comparatively lower efficacy of GnRH antagonists, which is likely to have influenced clinicians’ attitudes. This report describes GnRH antagonist utilization for ovarian stimulation in Germany from 2000–2003. Data from the national IVF registry were analysed. The majority of ovarian stimulation cycles are still performed in long GnRH agonist protocols, although a significant increase in GnRH antagonist usage has been noted (P < 0.0001). Two observations support the notion that GnRH antagonists are often utilized as a treatment option in cycles with an unfavourable a priori prognosis: (i) the proportion of GnRH antagonist cycles increases with cycle rank (P < 0.0001, χ² for linear trend); and (ii) GnRH antagonist cycles are more often conducted in older patients as compared to GnRH agonist cycles (P < 0.0001). This has important implications for interpreting clinical performance of GnRH antagonists outside a research context.