Abstract: Objective To investigate the value of serum beta-human chorionic gonadotropin (β-HCG) on days 9 (d9) and 11
(d11) after fresh embryo transfer (ET) and frozen-thawed embryo transfer (FET) in predicting the pregnancy outcomes.
Methods A total of 227 fresh ET and FET cycles performed at the Center of Reproductive Medicine, Qingyuan People’s
Hospital between Dec, 2012 and Feb, 2014 were analyzed. The data of serum β-HCG levels on d9 and d11 after fresh ET and
FET cycles and the pregnancy outcomes were reviewed, and the ROC curve was constructed to determine the optimal cut-off
level of serum β-HCG level for predicting pregnancy outcomes. Results According to pregnancy outcomes, the cycles were
divided into non-pregnancy group (group A), biochemical pregnancy group (group B), and clinical pregnancy group (group
C). Significant differences were found between the mean serum β-HCG levels measured on d9 and d11 in all the 3 groups (P<
0.01). The cycles in group C were further divided into 5 subgroups with single pregnancy (C1), twin pregnancy (C2), early
abortion (C3), ectopic pregnancy (C4), or intrauterine pregnancy complicated with ectopic pregnancy group (C5), and all the 5
subgroups showed significant differences in β-HCG measurements between d9 and d11 (P<0.01). On d9 after ET and FET, the
optimal cut-off level of serum β-HCG was 49.05 IU/L for predicting for clinical pregnancy, and was 105.15 IU/L for predicting
twin pregnancy; the two corresponding cut-off levels of serum β-HCG on d11 was 51.2 IU/L and 241.75 IU/L, respectively.
Conclusion The absolute serum β-HCG level on d9 and d11 after fresh ET and FET allows an accurate diagnosis of pregnancy
and helps in the prediction of the pregnancy outcomes.