Circulating luteinizing hormone level after triggering oocyte maturation with GnRH agonist may predict oocyte yield in flexible GnRH antagonist protocol.

BACKGROUND The use of gonadotrophin-releasing hormone (GnRH) agonist for triggering final oocyte maturation and ovulation can reduce ovarian hyperstimulation syndrome (OHSS) in high-risk patients. LH levels post-trigger with GnRH agonist might be correlated with oocyte yield and maturity. Our aim was to evaluate the relationship between serum LH level at 12-h post-trigger and oocyte yield, maturity and fertilization rate in patients at high risk of OHSS and therefore who were treated with a flexible GnRH antagonist protocol in which final oocyte maturation was triggered with GnRH agonist. METHODS In a prospective cohort study, 91 patients at high risk of OHSS were treated with a flexible GnRH antagonist protocol and divided into six groups according to their serum LH levels at 12-h after GnRH agonist administration: ≤15.0, 15.1-30.0, 30.1-45.0, 45.1-60.0, 60.1-75.0 and >75.0 IU/l. The oocyte yield, maturity, fertilization rate and clinical outcomes for each LH interval were analyzed. RESULTS There was a statistically significant reduction in oocyte yield with a concentration of serum LH ≤15.0 IU/l (P < 0.05), whereas no statistically significant differences in the oocyte maturity and fertilization rate among the six groups (P > 0.05) were seen. Only 5 out of 91 patients (5.5%) had a serum LH ≤15.0 IU/l at 12-h post-trigger with GnRH agonist. In addition, no statistically significant difference was seen regarding high-quality embryos, implantation rate, clinical pregnancy rate and early miscarriage between patients with LH ≤15.0 IU/l and >15.0 IU/l (P > 0.05). CONCLUSIONS Serum LH level at 12-h post-trigger with GnRHa <15.0 IU/l is associated with a dramatically lower oocyte yield but not with the oocyte maturity and fertilization rate. Serum LH levels post-trigger with GnRH agonist do not affect clinical outcomes.