COMPARING TWO PROTOCOLS FOR FINAL OOCYTE MATURATION IN POOR RESPONDERS UNDERGOING GnRH-ANTAGONIST ICSI CYCLES

Poor ovarian responders (POR) include a significant proportion of women referred for IVF treatments (ranging from 9 to 24 %), most of whom are in late reproductive age.(1,2) According to the "Bologna criteria", patients are classified as POR based on three conditions: if two or more of the following features are present: 1) advanced maternal age (>40 years); 2) a previous poor ovarian response (cycles cancelled or <3 oocytes with a conventional protocol); 3)an abnormal ovarian reserve test (antral follicle count 5-7 follicles or anti-Mullerian hormone 0.5-1.1 ng/ ml). Two of these criteria are required for a POR diagnosis. In addition, two cycles with POR after maximal stimulation are sufficient to classify a patient as a poor responder even in the absence of other criteria mentioned. (3)

In fact the live birth rate in the entire POR category is poor (about 6 % per cycle).(4,5) however patients <40 years have a significantly better prognosis compared to older patients, mainly due to better oocyte quality.(6) Attempts to improve IVF cycle outcomes for poor responders included modifying the steps of ovarian stimulation protocols , such as different luteal phase pretreatments, increasing ovarian stimulation doses, as well as addition of various supplements. So far, most of the modifications had limited success, therefore, optimal protocol for poor responders has remained elusive.(7)

ESHRE in 2019 stated GnRH antagonists and GnRH agonists are equally recommended for predicted low responders. (8)

Final oocyte maturation trigger is one of the most important key success factors in assisted reproductive technologies (ARTs). Oocyte maturation refers to a release of meiotic arrest that allows oocytes to advance from prophase I to metaphase II of meiosis. Luteinizing Hormone (LH) surge by dismantling the gap junctions between granulosa cells and oocyte inhibits the flow of maturation inhibitory factors into ooplasm and causes drop in concentration of cyclic AMP (cAMP) . Decreased concentration of cAMP in turn increases concentration of Ca and maturation-promoting factor (MPF), which are essential for the resumption of meiosis in oocyte and disruption of oocyte-cumulus complex triggering follicular rupture and ovulation about 36 h the LH surge.(9)

Until now, administering 5000 IU to 10,000 IU of hCG 34-36 h prior to oocyte retrieval remained the standard protocol for the induction of final oocyte maturation in IVF cycles worldwide. Traditionally, human chorionic gonadotropin (hCG) has been the trigger of choice for oocyte maturation due to its molecular and biological similarity with LH.(10)