The association of LH level on the stimulation outcomes of ICSI cycle triggered by GnRH agonist: a prospective cohort study

Background The short LH surge induced by a GnRH agonist (GnRHa) trigger minimizes the risk of ovarian hyperstimulation syndrome (OHSS), but its sufficiency to support optimal outcomes remains uncertain. This prospective cohort study evaluated the impact of pre- and post-trigger LH levels on the stimulation outcomes of GnRHa-triggered ICSI cycles. Methods Ninety-four women (≤ 40 years) undergoing GnRHa-triggered ICSI with a freeze-all approach were included. Ovulation was triggered using 0.3 mg triptorelin followed by 0.2 mg after 12 h. LH was measured on the trigger day and 12 h post-trigger. The primary outcome was oocyte maturation rate; secondary outcomes included fertilization and blastulation rates. Data were analyzed using Mann–Whitney, Pearson correlation and ROC curve analysis. Results Pre-trigger LH levels correlated with blastulation rates with modest predictive ability (AUC = 0.67). While post-trigger LH levels correlated significantly with oocyte maturation with modest predictive ability (AUC = 0.70). No significant associations were found with fertilization outcomes. Pre- and post-trigger LH levels were positively correlated ( r = 0.36, p = 0.01). Conclusions In GnRHa-triggered ICSI cycles, post-trigger LH levels were associated with oocyte maturation, while pre-trigger LH levels were associated with blastulation rate. However, discriminative performance was modest, and post-trigger LH data were available only in a subset of patients. These findings should be considered exploratory and require validation in larger prospective cohorts before clinical application.