The influence of serum luteinising hormone concentrations post GnRH agonist trigger on metaphase II oocytes in IVF/ICSI cycles

Gonadotropin-releasing hormone agonist (GnRHa) trigger is widely used in IVF/ICSI to reduce ovarian hyperstimulation syndrome (OHSS) risk, particularly in women with polycystic ovary syndrome (PCOS). However, the endocrine response is variable, and a threshold post-trigger luteinizing hormone (LH) level predictive of mature oocyte (metaphase II, MII) yield has not been clearly established. This study aimed to identify optimum and minimum LH levels measured 12 h after GnRHa trigger that are predictive of mature oocyte yield in PCOS patients.

This prospective, single-centre observational study included 104 PCOS patients undergoing controlled ovarian stimulation with a GnRH antagonist protocol. Final oocyte maturation was triggered with 2 ml Buserelin. Serum LH, FSH, and progesterone were measured 12 h post-trigger. The primary outcome was the correlation between hormone levels and MII oocyte yield.

Mean LH at 12 h post-trigger was 34.05 IU/L (SD 23.07, range 0.9-134.4 IU/L). No significant correlation was found between LH and MII yield (r = -0.123; p = 0.215), fertilisation rate (r = 0.046; p = 0.641), or blastocyst formation (r = 0.162; p = 0.101). FSH and progesterone also showed no significant associations. ROC analysis showed poor predictive value of LH for mature oocyte yield (AUC = 0.402). MII yields varied widely across LH levels, with no identifiable minimum or optimum threshold.

No LH threshold at 12 h post-GnRHa trigger predicted optimal or suboptimal oocyte maturation. Routine post-trigger LH measurement lacks clinical utility for predicting mature oocyte yield in PCOS IVF/ICSI cycles.