Human chorionic gonadotropin levels after blastocyst transfer are highly predictive of pregnancy outcome

Objective: To determine the predictive value(s) of β-hCG serum levels for pregnancy outcome following blastocyst transfer. Design: Retrospective review. Setting: University-based assisted reproductive technology (ART) program. Patients: All ART patients enrolled from January 1998 to December 1999.Intervention(s): None. Main Outcome Measure(s): β-hCG serum levels and pregnancy outcomes. Result(s): Of the 836 ART cycles initiated, 608 embryo transfers met study criteria and were assigned to one of two groups: 248 day 5 blastocyst transfers or 360 day 3 embryo transfers. In the day 5 blastocyst group, 147 pregnancies occurred (59.2%), and day 3 transfers resulted in 165 pregnancies (45.8%). For day 3 and day 5 transfers, mean values of β-hCG on day 16 post-retrieval of spontaneous abortions were lower than ongoing pregnancies (P<.05). A β-hCG value on day 16 of >300 mIU/mL predicted an ongoing pregnancy for day 5 transfer group in 97% of pregnancies compared with 92% for day 3 embryo transfers. A multiple gestation was observed in 70% of pregnancies with a β-hCG level >400 mIU/mL in the day 5 group compared with 63% for the day 3 group. The incidence of higher-order multiple gestations was significantly lower in the day 5 blastocyst group (P<.05). Conclusion(s): β-hCG serum levels on day 16 post-retrieval were highly predictive of pregnancy outcome after a blastocyst transfer.