Racial disparities in the outcomes of euploid single frozen-thawed embryo transfer cycles - analysis of the Clinical Outcome Reporting System of the Society for Assisted Reproductive Technology 2016-2018 data.

Objective: To evaluate if in pregnancies conceived with the transfer of single genetically tested embryos, maternal race and ethnicity relate to pregnancy outcome.

Design: Retrospective cohort.

Setting: Data available in the Clinical Outcome Reporting System of the Society for Assisted Reproductive Technology (SART-CORS) for years 2016-2018.

Patient(s): Autologous frozen-thaw embryo transfer (FET) cycles with transfer of single genetically tested embryo in SART-CORS for years 2016-2018; cycles associated with diagnoses of recurrent pregnancy loss, gestational carrier, donor egg and donor embryo were excluded.

Intervention(s): Information on race and ethnicity linked with in vitro fertilization and FET cycles available in SART-CORS.

Main outcome measure(s): Multivariable analyses using generalized estimating equation examined the relationship between categories of race and ethnicity with the following outcomes: Pregnancy positive β hCG (human chorionic gonadotropin), clinical pregnancy, pregnancy loss (early [at gestation <13 weeks] and late [loss between ≥13 and <20 weeks]), preterm (<37 weeks), term (≥37 weeks) and live birth. Covariates adjusted for included age, body mass index, anti-Mullerian hormone, infertility diagnosis and smoking history.

Result(s): Seventy-nine thousand four hundred and sixteen FET cycles met the eligibility criteria. Information on race and ethnicity was specified for 50,820 (64.0%) and was not known in 28,723 (36%) of the cycles. The population was predominantly non-Hispanic White (44%); non-Hispanic Black comprised 2.7%, Asian 12.3%, Hispanic 3.4%, and American Indian, Pacific Islander, Hawaiian, and Alaskan comprised 0.2% of the population. Nearly 1.0 % self-identified with more than one race. On multivariable analyses, pregnancies in non-Hispanic Black and in Hispanic women (compared with non-Hispanic Whites') were significantly more likely to result in in preterm birth. Compared with non-Hispanic White women, the likelihood of live birth was significantly lower in non-Hispanic Blacks, Asian, Hispanic, American Indian, Pacific Islander, Hawaiian, and Alaskan women. The likelihood for delivery by Cesarean was also disproportionately higher in the non Hispanic Black and, Hispanic women and in those identifying with more than one race (0.023) compared with non-Hispanic White women.

Conclusion(s): Racial and ethnic differentials are apparent in the outcomes of FET conceived pregnancies resulting from the transfer of single genetically tested embryos.