Exploratory cohort study into underlying mechanism of differences in estrogen metabolism between Asian and Caucasian women during assisted reproductive technology treatment

Objective

Explore whether racial differences in prevalence of CYP1A2∗1F polymorphism underlies estrogen metabolism differences among Asians and Caucasians.

Design

Prospective cohort study.

Setting

University-based fertility practice.

Patient(s)

Asian or Caucasian patients who underwent ovarian stimulation (OS) or programmed cycle frozen embryo transfer (FET) between October 2019 and April 2021.

Intervention(s)

None.

Main Outcome Measure(s)

Trigger-day serum E2 per oocyte retrieved in OS cycles, and E2 on day of lining check in FET cycles.

Result(s)

Seventy-one participants were enrolled, 55 in OS group (29 Caucasian and 26 Asian) and 16 in FET group (10 Caucasian and 6 Asian). Peak E2 per oocyte retrieved in the OS group (n = 48) differed by race, with significantly lower levels in Caucasians compared with Asians (177.5 ± 64.2 vs. 261.1 ± 139.5 pg/mL). Prevalence of CYP1A2∗1F polymorphism did not significantly differ by race. Compared using Kruskal–Wallis test, peak E2 per oocyte retrieved did not differ by CYP1A2∗1F genotype. In multivariate linear regression model, adjusting for body mass index, caffeine intake, and self-reported race, there remained no significant correlation. In FET group, serum E2 on day of lining check was also not significantly different by CYP1A2∗1F genotype.

Conclusion(s)

Although a consistent difference in serum E2 between Asians and Caucasians undergoing OS was noted, the CYP1A2∗1F polymorphism is unlikely the primary driver of this difference.