Maturity rates (MR) with GnRH-agonist (GnRH-A) trigger in normal, low, and very-low responders pursuing elective oocyte cryopreservation (EOC)

Abstract

GnRH-a is a well-established method for oocyte maturation in high-responders at risk for ovarian hyperstimulation syndrome (OHSS). While normal and low responders are at lower risk for OHSS, even a small risk may be unacceptable in EOC. The primary objective of this study is to evaluate MR in normal, low, and very-low responders undergoing EOC using GnRH-a trigger. Retrospective Cohort. All EOC cycles performed from April 2016-April 2018 at Extend Fertility Medical Practice, a large single-center oocyte cryopreservation program, were included in the study. Demographic, clinical, and embryologic data were collected and categorized from the electronic medical record. MR was calculated using the quotient of mature (MII) and retrieved oocytes. Peak estradiol (E2) levels on day of trigger were used as a surrogate for ovarian response. Associations were made using X2, student’s t-test, Mann-Whitney U, and Kruskall Wallace, where appropriate. 1125 total cycles, 491 (43.6%) GnRH-a, 609 (54.13%) hCG, and 24 (2.1%) dual-trigger (DT) cycles were included. Mean retrieved and MII oocytes were 15.9±10.9 and 10.8±8.4. Both were significantly higher in GnRH-a (19.5±12.8, 13.7±9.8) compared to hCG (13.0±8.0, 8.5±9.2) and DT (14.9±7.7, 10.7±6.2) (p<0.01). Median MR(IQR) was 0.70(0.26) overall. MR for hCG [0.67(0.25)] was significantly lower than the GnRH-a [0.74(0.25)] and DT [0.78(0.21)] (p<0.01). Mean E2 level was 2352.9±1485.5 pg/mL overall and was significantly lower for hCG compared to GnRH-a (1872.1±912.0 vs. 2974.0±1810.0, p<0.01). Table 1 demonstrates oocytes retrieved, MII, and MR for GnRH-a categorized by E2 level on day of trigger. While mean oocytes retrieved and MII were significantly higher in the higher E2 groups, the MR was not significantly different. 45/487 (9.0%) of GnRH-a triggers were categorized as very-low responders (peak E2<1000). Median MR was significantly lower for E2<1000 compared to E2>1000 [0.64(0.26) vs. 0.75(0.23), p=0.002]. Overall, there were a total of 174 very-low responders, 126 (71.2%) hCG, 45 (25.4%) GnRH-a, and 3 (1.7%) DT. The median MR for very-low responders was 0.66(0.34) and did not significantly differ between hCG and GnRH-a [0.68(0.45) vs 0.65(0.26), p=0.10]. GnRH-a trigger is a suitable option for women undergoing EOC, where even a small risk of OHSS may be unacceptable. No significant decline was seen in MR when used in normal and low responders undergoing EOC. Very-low responders had lower MR overall, regardless of trigger type. Based on these data, GnRH-a can be used reliably for the induction of maturation in EOC cycles regardless of response.TABLE 1"Low" (E2<2000) n=160"Normal" (E2 2001-3000) n=116"High" (E2 3001-4000) n=91"Very-High" (E2>4000) n=111p-valueOocytes retrieved Mean±SD9.56±6.8620.21±10.0923.63±10.6830.08±12.81<0.001MII oocytes Mean±SD6.69±4.9013.88±8.4316.13±8.8021.61±10.30<0.001MR Median (IQR)0.72 (0.26)0.75 (0.22)0.75 (0.22)0.76 (0.22)0.78 Open table in a new tab