We aimed to evaluate the effect of serum luteinizing hormone (LH) levels on human chorionic gonadotropin (HCG) injection day (LHHCG) on outcomes of in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) patients. It is a retrospective cohort study involving 620 women who had an IVF cycle in Taizhou Hospital Affiliated to Wenzhou Medical University between 2018-2020. The participants were divided into different groups according to LHHCG level and age. The clinical data and outcomes were compared between groups. The numbers of follicles (≥ 14 mm) on HCG day, retrieved oocytes, mature oocytes, and two pronuclei (2PN) embryos in women with LHHCG < 2 IU/L were more than those with LHHCG ≥ 2 IU/L. Women with LHHCG < 2 IU/L had lower high-quality embryo rate (42.2% vs. 46.5%, p = 0.002) and implantation rate (40.0% vs. 58.8%, p = 0.044) compared to those with LHHCG ≥ 2 IU/L. When LHHCG < 2 IU/L, there was no significant difference in implantation rates in patients < 35 years compared to those ≥ 35 years. When LHHCG ≥ 2 IU/L, patients < 35 years old had higher implantation rates (71.7% vs. 41.2%, p < 0.001) compared to those ≥ 35 years old. The success rates of IVF fertilization and ICSI fertilization and biochemical and clinical pregnancy rates were not significantly different between groups. Our results demonstrated that women undergoing IVF/ICSI-ET might benefit from maintaining LHHCG levels at ≥ 2 IU/L. In addition, age might associate with LHHCG levels and be a better determining factor of the transfer outcome than serum LHHCG levels for IVF/ICSI-ET.
Keywords: IVF/ICSI-ET; gonadotropin-releasing hormone antagonist; human chorionic gonadotropin; luteinizing hormone; pregnancy outcomes.