Follicular challenge test to predict suboptimal response to gonadotropin releasing hormone agonist trigger in elective oocyte cryopreservation cycles.

ABSTRACT

This prospective study aimed to test the ability of follicular GnRH agonist challenge test (FACT) to predict suboptimal response to GnRH agonist trigger, assessed by LH levels post ovulation trigger in non-medical oocyte cryopreservation program. The study included 91 women that underwent non-medical fertility preservation. On day two to menstrual cycle, blood tests were drawn (basal Estradiol, basal FSH, basal LH, Progesterone) and ultrasound (US) was performed. On that evening, the women were instructed to inject 0.2 mg GnRH agonist (FACT) and arrive for repeated blood workup 10-12 h later in the next morning, followed by a flexible antagonist protocol. LH levels on the morning after ovulation trigger were compared to FACT LH levels. The results demonstrated that LH levels following agonist ovulation trigger below 15IU/L occurred in 1.09% of cycles and were predicted by FACT, r = 0.57, p < 0.001. ROC analysis demonstrated that FACT LH > 42.70 IU/L would predict LH post trigger of more than 30 IU/L with 75% sensitivity and 70% specificity, AUC = 0.81. LH levels post trigger also displayed significant positive correlation to basal FSH (r = 0.35, p = 0.002) and basal LH (r = 0.54, p < 0.001). LH levels post ovulation trigger were not associated with total oocytes number or maturity rate. The strongest correlation to the number of frozen oocytes was progesterone levels post agonist trigger (r = 0.746, p < 0.001). We concluded that suboptimal response to agonist trigger, as assessed by post trigger LH levels was a rare event. FACT could serve as an adjunct pre-trigger, intracycle tool to predict adequate LH levels elevation after agonist ovulation trigger. Future studies should focus on optimization of agonist trigger efficacy assessment and prediction, especially in high responders.