The predictive value of an initial serum beta human chorionic gonadotropin level for pregnancy outcome following in vitro fertilization

Purpose: Our purpose was to assess the predictive value for pregnancy outcome of an initial serum quantitative beta-hCG measurement obtained 11 or 12 days after embryo transfer in an in vitro fertilization program. Methods: A prospective, descriptive study of 153 pregnancies achieved via in vitro fertilization-embryo transfer was performed. Initial beta-hCG levels and subsequent pregnancy outcomes were compared. Results: The overall mean initial beta-hCG level was 91+/-85.8 mIU/ml for normal (singleton, multiple-gestation) pregnancies and 29+/-24.9 mIU/ml for abnormal (miscarriage, ectopic) pregnancies (P <0.01; power; >80%). While 93.9% of patients with initial beta-hCG levels greater than or equal to 42 mIU/ml had normal pregnancies, 56.4% of those with initial levels <42 mIU/ml experienced abnormal outcomes. With 42 mIU/ml as the cutoff level for predicting a normal pregnancy, this screening test yielded a sensitivity of 79.3% and a specificity of 83.8%. Conclusions: Initial serum beta-hCG levels obtained 11 or 12 days after embryo transfer may be predictive of pregnancy outcome in an in vitro fertilization program.