Serum HCG measured in the peri-implantation period predicts IVF cycle outcomes.

The current study assessed the relationship between serum concentrations of human chorionic gonadotrophin (HCG) measured in the peri-implantation period and various outcome measures following blastocyst transfer in IVF cycles. The study group included 767 autologous IVF cycles, each with the transfer of two fresh blastocysts in a 6-year study period, ending 31 December 2009. Outcome measures were ectopic pregnancy, biochemical pregnancy loss, ongoing pregnancy, spontaneous abortion and multiple pregnancy. Peri-implantation serum HCG concentration measured 5 days after blastocyst transfer was highly predictive of these outcome measures. These findings suggest embryonic implantation and developmental fate are largely determined by 5 days after blastocyst transfer and that very early serum HCG measurements may be useful markers of IVF outcome.