Serum human chorionic gonadotropin can predict live birth 7 days after frozen-thawed blastocyst transfer

To study the earliest timepoint at which serum human chorionic gonadotropin (hCG) can predict live birth after blastocyst frozen embryo transfer, and to determine the cutoff values for hCG levels on days 7-11 after frozen-thawed embryo transfer with blastocysts.

Single-center retrospective cohort study.

We investigated 18,491 cycles of frozen-thawed blastocyst transfers at our hospital between January 2016 and December 2022.

Not applicable.

The hCG cutoff values for live birth on days 7-11 after frozen-thawed blastocyst transfer.

Receiver operating characteristic analysis between serum hCG levels and live birth after frozen-thawed blastocyst transfer showed area under the curve values of 0.962, 0.958, 0.954, 0.957, and 0.954, for days 7, 8, 9, 10, and 11, respectively. Serum hCG cutoff values from the 7th to 11th days after frozen-thawed blastocyst embryo transfer were 31.05 mIU/mL, 46.6 mIU/mL, 72.05 mIU/mL, 95.4 mIU/mL, and 159.9 mIU/mL, respectively.

We determined the hCG cutoff values for live births after frozen-thawed blastocyst transfer. We suggest that it is possible to predict pregnancy outcomes as early as the 7th or 8th day after frozen-thawed blastocyst transfer.