Study question: Is severe early ovarian hyperstimulation syndrome (OHSS) completely prevented with the GnRH agonist trigger and 1500 IU hCG luteal rescue protocol?
Summary answer: Severe early OHSS can occur even after the GnRH agonist trigger and 1500 IU hCG luteal rescue protocol.
What is known already: Prior studies including over 200 women who received the GnRH agonist trigger and 1500 hCG luteal rescue protocol have reported complete prevention of severe early OHSS. Only a few late OHSS cases have been reported and it has been suggested that this protocol can be safely applied to any women under risk.
Study design, size, duration: This retrospective cohort study included all women who were at high risk of OHSS and were given the GnRH agonist trigger plus hCG luteal rescue protocol between December 2008 and August 2012 in the two participating centers.
Participants/materials, setting, methods: There were 23 women with a mean estradiol level of 4891 ± 2214 pg/ml and a mean number of >12 mm follicles of 20 ± 6 on the day of ovulation triggering. OHSS was categorized according to the Golan criteria.
Main results and the role of chance: Overall 6 of the 23 (26%) women developed severe OHSS. Five women had severe early OHSS requiring ascites drainage and hospitalization and three of these women did not undergo embryo transfer. The number of follicles measuring 10-14 mm on the day of triggering was significantly different between women who developed severe early OHSS and those who did not.
Limitations, reasons for caution: The small number of women with severe early OHSS may have prevented identification of other significant risk factors.
Wider implications of the findings: Although the GnRH agonist plus 1500 IU hCG luteal rescue protocol significantly decreases the risk of severe OHSS, this life threatening complication can still occur in high-risk patients. It would be prudent to avoid hCG luteal rescue and freeze all embryos for future transfer in such women particularly when there are ≥18 follicles with 10-14 mm diameters even with few larger follicles.
Keywords: GnRH agonist; GnRH antagonist; hCG; in vitro fertilization; ovarian hyperstimulation syndrome.