Live birth associated with peak serum estradiol levels in letrozole intrauterine insemination cycles.
- 2023
CONCLUSION: In letrozole ovulation induction cycles followed by intrauterine insemination, lower LBR and clinical pregnancy rates were found in women with lower E2 concentrations compared with higher E2 concentrations at the 25th, 50th, and 75th percentile E2 concentration quartiles. Where possible, delaying HCG trigger until E2 concentration rises following aromatase inhibition and approaches physiologic periovulatory concentration may improve pregnancy rates with letrozole followed by intrauterine insemination. Copyright � 2023. Published by Elsevier Inc. DESIGN: Retrospective cohort study SETTING: Large, multi-center private practice PATIENTS: A total of 2,368 OI-IUI cycles in patients treated with letrozole followed by IUI were evaluated from January 1, 2014 - July 31, 2019. INTERVENTIONS: Ovulation induction with letrozole, followed by autologous IUI MAIN OUTCOME MEASURES: The primary outcome measure was LBR as a function of serum E2 concentration at the time of hCG administration or LH surge, adjusting for age, BMI, largest follicle diameter, and number of follicles > 14 mm. Clinical pregnancy rate as a function of E2 concentration, pregnancy rate as a function of lead follicle diameter, and pregnancy loss rates were secondary outcome variables. OBJECTIVE: To identify whether estradiol (E2) serum concentration around the day of hCG trigger or LH surge (hCG-LH) was associated with livebirth rate (LBR) during ovulation induction (OI) or controlled ovarian hyperstimulation (COH) with letrozole followed by intrauterine insemination (IUI). RESULTS: 2,368 cycles met inclusion criteria. Outcomes were evaluated at the 25th (E2 110 pg/ml), 50th (157 pg/ml), 75th (225 pg/ml), and 90th (319 pg/ml) percentiles. LBR ranged from 9.4% - 11.1% in the lower E2 cohorts, and 12.5%-13.5% in the higher E2 cohorts. LBR was significantly greater in the cohort of women with higher E2 concentrations in all percentile comparisons except for the 90th percentile. Mean diameter of peri-ovulatory follicle diameter >20 mm or <20 mm was not independently associated with live birth rate or clinical pregnancy rate, despite a significantly higher mean E2 level in the larger follicle group.