【Objective】To compare early serum beta-human chorionic gonadotropin (β-hCG) levels after cleavage or blastocyst embryo transfers (ET) in predicting pregnancy outcome.【Methods】A total of 2 421 IVF-ET cycles in our center performed from June 2010 to May 2015 and resulted in clinical intrauterine pregnancies were analyzed retrospectively. The predictive value was compared between β-hCG on day 14 after cleavage ET and β-hCG on day 12 after blastocyst ET.【Results】Serum β-hCG levels of patients re? sulted in clinical intrauterine pregnancies were significantly higher with blastocyst ET compared with cleavage ET. This significant dif? ference was also existed in patients resulted in miscarriage

ongoing pregnancy (OP) or live birth (LB). However

this significant differ? ence was only existed in frozen embryo transfers. For a frozen cleavage ET

the cut-off value was 475 U/L (sensitivity 79%

specificity 61.3%) in predicting LB. For a frozen blastocyst ET

the cut-off value was 575 U/L (sensitivity 74.9%

specificity 59.2%) in predicting LB.【Conclusion】In frozen embryo transfers

early serum β-hCG level after blastocyst ET is higher than cleavage ET. The cut-off val? ue in predicting pregnancy outcome is different according to the stage embryo transferred. Early serum β-hCG can effectively predict live birth after blastocyst or cleavage ET.