OBJECTIVETo 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.

METHODSA 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.

RESULTSAccording 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.

CONCLUSIONThe 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.