P-739: GnRH antagonist is a reliable ovarian stimulation regimen for IVF treatments

Abstract

In the six years since introduction of GnRH antagonists, it has been shown that treatment duration and gonadotropin consumptions have decreased during ART cycles. However, success rates with GnRH-ant use have been questioned (Griesinger et al; 2005). Our objective with this study was to review success rates during a period that our practice used GnRH-antagnist as the primary choice IVF protocol. Retrospective study (11/2001 - 8/2005). This study was a retrospective chart review including all GnRH-antagonist treatment cycles with fresh embryo transfer from 11/01 through 8/05. Patients were pretreated with approximately three weeks of oral contraceptive pills starting on day 3 of menses. Gonadotropin stimulation was initiated on day 2-4 of their subsequent menses. GnRH-antagonist (Antagon/Ganirelix) initiation was variable based upon follicle diameter (∋14), estradiol levels (>400), and usually occurred on day 5 or 6 but as early as day 4 of stimulation. GnRH-antagonist dosing usually was 250μg SQ, but occasionally 500μg SQ, each day through and including the day of hCG (10,000 iu IM) administration. Gonadotropin dosing was variable and hCG was administered when at least three follicles reached a mean diameter of at least 18mm. No gonadotropin was given on the day of hCG. Oocyte retrieval was performed 35-37 hours after hCG. Embryo transfer was performed typically on day 3, but occasionally on day 5 (e.g. when single embryo transfer was desired). Clinical pregnancy was defined as ultrasound evidence of an intrauterine embryonic pole with heartbeat by the 5th week following oocyte retrieval. 94% of GnRH-antagonis cycles triggered with hCG between day 9-11 of GnRH administration. Length of gonadotropin stimulation did not differ with patient’s age. It also did not correlated with either E2 or P4. Clinical pregnancy rates did not very with the length of stimulation days i.e. 41.7%, 50.0%, 38.5% and 33.3% for hCG on day 9, 10, 11 and 12. Clinical pregnancy rates as expected did trend lower with patient’s age although there was no significant difference was found, i.e. 56.5%, 39.3%, 33.3% and 56% for age of ≤ 34, 35-37, ≥38 years old and donor groups respectively. There were no significant difference in E2 and P4 between age groups, except for the donors who had higher P4 on the day of hCG with 1.72 ± 0.22 ng/ml that was significantly higher than patient’s group with age ≤ 34 (1.24 ± 0.051 ng/ml P≤0.001), 35-37 (1.19 ± 0.057 ng/ml P≤0.001) and 38-40 years old (1.34 ± 0.090 ng/ml P≤0.05) respectively. These data suggest that pregnancy rates after GnRH-antagonist treatment are acceptable for all age groups and for donor cycles. Also, this review suggests that stimulations with GnRH-antagonist may be expected to trigger, on average, one day sooner comparing to our previous experience with using agonist. Notably, during oocyte donor stimulations, progesterone levels increased, which may be a result of their younger age.