Effects of low LH serum levels on oocyte retrieval, fertilization rate and embryo quality during controlled ovarian stimulation: results from a prospective cohort analysis

Objectives: Luteinizing hormone plays a key role in normal follicular development and oocyte maturation in controlled ovarian stimulation. Luteinizing hormone stimulates the proliferation and differentiation of theca cells for the secretion of androgens, synergistically increasing estrogen production. This study aimed to investigate the effects of low luteinizing hormone concentrations on oocyte retrieval, fertilization and embryo development in patients undergoing in vitro fertilization/intracytoplasmic sperm injection. Design: We prospectively (ClinicalTrials iD: NCT05755529) analyzed patients undergoing in vitro fertilization/intracytoplasmic sperm injection, subdividing them into three groups according to their age. Serum luteinizing hormone levels were evaluated on day 3, during stimulation (day 10) and before ovulation induction (day 12). Participants/materials, setting, methods: 43 consecutive women were scheduled for IVF and received ovarian stimulation with follitropin alfa (Gonal F, Merck Serono, Germany) and ganirelix (Fyremaldel, Sun Pharma, Italy). Statistical analysis was performed with InStat 3.10, GraphPad software, San Diego, CA. Normal distribution was tested by the Shapiro‒Wilk test. Continuous variables were expressed as the mean and standard deviation (SD). Categorical variables are expressed as frequencies and percentages. Results Our data analysis suggests that serum luteinizing hormone levels progressively decrease during controlled ovarian stimulation, and this effect is more evident in the early phase of this procedure. From this perspective, circulating luteinizing hormone levels may significantly decrease during the late follicular phase due to the negative feedback of ovarian hormones from multiple follicular developments or after the suppressive effects of gonadotropin-releasing hormone antagonists. Limitations Although our study confirms that exogenous LH can be considered as a strategy in women with reduced LH levels during ovarian stimulation to improve oocyte quality and reproductive outcome, the generalizability of the results is limited by the low number of participants enrolled. Conclusions Exogenous luteinizing hormone may be considered a strategy in women with a decrease in luteinizing hormone levels during ovarian stimulation to improve oocyte quality and reproductive outcome.