Rescue in vitro fertilization using a GnRH antagonist in hyper-responders from gonadotropin intrauterine insemination (IUI) cycles.

Objective: To evaluate the outcomes in the conversion of high-response gonadotropin intrauterine insemination (IUI) cycles to "rescue" in vitro fertilization (IVF) using a Gonadotropin-Releasing Hormone (GnRH) antagonist, with regards to implantation rates, pregnancy rates, cost, and ovarian hyperstimulation syndrome (OHSS) as compared to matched, hyper-responder, IVF controls.

Methods: This prospective cohort study was conducted between January 2007 and December 2009 at our institution. In order to decrease high-order multiple pregnancy, minimize the incidence of OHSS, and avoid cycle cancellation, high-response stimulated-IUI patients opted to convert to "rescue" IVF using the GnRH antagonist cetrorelix acetate. We then compared their clinical outcomes with matched patients from high-response IVF cycles of the standard long mid-luteal GnRH agonist protocol (14 or more collected oocytes). Only cases of conventional IVF without intra-cytoplasmic sperm injection (ICSI) were included in the control group.

Results: Out of 184 patients undergoing stimulated-IUI cycles with gonadotropins, 87 patients developed a hyper-response, and 20 opted to convert to "rescue" IVF. These patients were compared with 157 matched, hyper responder IVF controls from our registry. The implantation rate was 25.6 % in the "rescue" IVF group and 20.7 % in the control IVF group (p < 0.0047). The ongoing clinical pregnancy rate per embryo transfer was 45.0 % and 33.6 % in the "rescue" IVF and the control IVF groups, respectively (p < 0.0001). The mean duration of stimulation was comparable between cohorts (10.0 vs.10.4 days, p = 0.6324). The mean dose of gonadotropin used per cycle was higher in the control group, 2664 international units (IU) of follicle stimulation hormone (FSH) compared to 1450 IU of FSH in the "rescue" IVF group (p < 0.0001). The incidence of severe OHSS is also higher in the control group, 5.1 % versus no cases in the "rescue" IVF group (p < 0.0001).

Conclusion: Our study demonstrates that conversion of high-response gonadotropin-IUI cycles to "rescue" IVF using a GnRH antagonist is a cost-effective strategy that produces better results than regular IVF with relatively minimal morbidity, and shorter duration to achieve pregnancy. Implantation and ongoing clinical pregnancy rates tend to be higher than those from hyper-responder regular IVF patients.