Co-administration of Low Dose hCG at the Time of GnRH Agonist Trigger or 35 Hours Later for the Prevention of OHSS

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of controlled ovarian hyperstimulation which may result in significant morbidity and rarely mortality as well as significant financial and psychological distress. GnRH agonist trigger has been shown to be effective in OHSS prevention. However, the adoption of its use has not been widely accepted in view of concerns regarding potential impairment of implantation. Intensive luteal phase supplementation with estrogen (E2) and progesterone (P) is important due to the strong evidence of abnormal luteal phase serum E2 and P profiles. However, it has been shown that optimal conception rates is not achieved for high risk patients with peak serum E2 \< 4,000 pg/ml despite aggressive steroidal supplementation. It has been proposed that the use of adjuvant low dose hCG at the time of GnRH agonist trigger or 35 hours later will rescue some of the corpora lutea and help improve corpora lutea function and improve pregnancy rates. The study will evaluate patients at high risk of OHSS development with peak serum E2 \< 4,000 pg/mL to determine whether timing of low dose hCG administration affects ongoing pregnancy rates or risk of OHSS. Markers of corpus luteum function such as serum 17 hydroxy-progesterone and prorenin during the luteal phase and early pregnancy will help elucidate further the effect of adjuvant low dose hCG with GnRH agonist trigger on corpus luteum function.