Racial/ethnic variation in ovarian responsiveness and live birth after in vitro fertilization

To evaluate racial/ethnic variation in ovarian responsiveness to stimulation during in vitro fertilization (IVF); and to compare the association between ovarian responsiveness and live birth by race/ethnicity.

Retrospective cohort study.

Women who underwent ovarian stimulation for IVF between 2017 and 2019 as reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System.

Race/ethnicity (Asian, Black, Hispanic, Other/Mixed, White); and ovarian sensitivity index (OSI).

Ovarian sensitivity index (number of oocytes retrieved/total gonadotropin dose ×1,000) adjusting for age at retrieval, body mass index, reporting year, number of prior cycles, antimüllerian hormone, and infertility diagnosis; and cumulative live birth adjusting for the above confounders and stratified by race/ethnicity.

A total of 246,132 retrieval cycles with race/ethnicity data were included: 46,939 (19.1%) among Asian patients, 17,013 (6.9%) among Black, 18,334 (7.4%) among Hispanic, 2,817 (1.1%) among Other/Mixed, and 161,029 (65.4%) among White. Adjusting for confounders, Black participants had a higher OSI compared with White participants (5.4, 95% confidence interval [CI] 5.1-5.5, vs. 5.1, 95% CI 5.1-5.1) and Asian participants had a lower OSI (4.8, 95% CI 4.1-4.8). Of the retrieval cycles, 68,107 resulted in fresh embryo transfers, and a total of 169,405 frozen embryo transfers were performed. Despite higher OSI, Black participants had lower cumulative live birth compared with White participants (45.5% vs. 60.8%). When stratifying by race/ethnicity, higher OSI was consistently associated with an increased odds of cumulative live birth (adjusted odds ratio [aOR] ranging from 1.23, 95% CI 1.01-1.48, for Other/Mixed to 1.49, 95% CI 1.41-1.53, for White), with no significant difference in the strength of association by race/ethnicity.

Higher ovarian responsiveness is associated with increased odds of cumulative live birth. However, despite higher ovarian responsiveness to stimulation, Black participants experience lower odds of cumulative live birth compared with White participants. This disparity in IVF outcomes likely arises from factors beyond differences in responsiveness to stimulation.