Reproductive outcome of fresh or frozen-thawed embryo transfer is similar in high-risk patients for ovarian hyperstimulation syndrome using GnRH agonist for final oocyte maturation and intensive luteal support.

BACKGROUND Triggering ovulation by GnRH agonist (GnRHa) in GnRH antagonist IVF protocols coupled with adequate luteal phase support has recently been suggested as a means to prevent ovarian hyperstimulation syndrome (OHSS). Our objective was to examine the outcome of fresh embryo transfer (f-ET) after triggering ovulation by GnRHa and providing intensive luteal phase supplementation, compared with that of the next first frozen-thawed embryo transfer (ft-ET) after cycles with the same protocol and cryopreservation of all the embryos. METHODS We performed a cohort study at a university-based IVF clinic. The study population was patients at high risk for OHSS. A daily dose of 50 mg i.m. progesterone in oil and 6 mg of oral 17-β-estradiol initiated on oocyte retrieval day in the f-ET group (n= 70). In the ft-ET group (n= 40) the embryos were cryopreserved and transferred in the next cycle. RESULTS The live birth rate per f-ET was 27.1 versus 20% in the ft-ET groups [P = 0.4; rate ratio = 1.36 (0.65-2.81)]. The implantation, pregnancy and spontaneous abortion rates were comparable in both groups. None of the patients developed OHSS. CONCLUSIONS In this observational cohort study, we showed that triggering ovulation with GnRHa and intensive luteal phase support is a promising new modality to prevent OHSS without the cost of cycle cancellation, ET deferral and reduced clinical pregnancy rates. Confirmation of these findings by RCTs is now required.