Black race associated with lower live birth rate in frozen-thawed blastocyst transfer cycles: an analysis of 7,002 Society for Assisted Reproductive Technology frozen-thawed blastocyst transfer cycles

In this large cohort, racial/ethnic differences persist in FET cycle pregnancy outcomes. Black race remains an independent predictor of reduced LBR, likely due to the significantly higher CLR.

VOLUME 117, ISSUE 2, P360-367


Reeva Makhijani, M.D., Prachi Godiwala, M.D., James Grady, Dr.P.H., Alicia Christy, M.D., Kim Thornton, M.D., Daniel Grow, M.D., Lawrence Engmann, M.D.



To evaluate if racial/ethnic differences in pregnancy outcomes persisted in frozen-thawed embryo transfer (FET) cycles on a national level.


Retrospective cohort study.


Clinic-based data.


A total of 189,000 Society for Assisted Reproductive Technology FET cycles from 2014–2016 were screened, of which 12,000 cycles had available fresh cycle linkage information and ultimately, because of missing data, 7,002 FET cycles were included. Cycles were stratified by race (White, Black, Asian, and Hispanic).



Main Outcome Measure(s)

The primary outcome was live birth rate. Secondary outcomes were implantation rate, clinical pregnancy rate, multiple pregnancy rate, and clinical loss rate (CLR).


Live birth rate was significantly lower in the Black vs. White and Asian, but not Hispanic group. Implantation rate was also significantly lower and CLR higher in the Black group compared with all other groups (all P<.01). Black women had a lower risk of live birth (adjusted risk ratio, 0.82; 95% confidence interval [CI], 0.73–0.92) and a higher risk of clinical loss (adjusted risk ratio, 1.59; 95% CI, 1.28–1.99) compared with White women. There was no significant difference between groups in clinical pregnancy rate or multiple pregnancy rate. When the analysis was limited to preimplantation genetic testing FET cycles, there remained a significantly lower implantation rate in the Black group compared with all other groups (all P<.01).


Black race remains an independent predictor of reduced live birth rate in FET cycles, likely because of higher CLR.