Predictive value of early serum β-hCG levels after single blastocyst transfer

Abstract

Objective. Analysis of serum β-human chorionic gonadotropin (β-hCG) levels on standardized days after oocyte retrieval (OR) following single blastocyst transfer to predict pregnancy outcome after assisted reproductive technology. Design. Retrospective study. Setting. Private fertility center. Population. A total of 230 women with an intact intrauterine pregnancy 21 days after OR and a vital term delivery (n 191) or a miscarriage (< 100 gestational weeks) (n 39) in the course of the pregnancy following single blastocyst transfer between 1999 and 2008. Methods. Blood was sampled 11, 14 and partly 21 days after OR. The serum concentration of total β-hCG was measured by an automated quantitative immunoassay. Receiver operating characteristic curves were generated to calculate sensitivity and specificity. Main outcome measures. A total of 509 β-hCG measurements. Results. The mean β-hCG concentrations on days 11, 14 and 21 after OR were significantly lower in the group of patients with a miscarriage compared to the group with a term delivery (p 0.02, < 0.001 and < 0.001 respectively). With the cut-off values of 15 mIU/mL, 80 mIU/mL and 1500 mIU/mL on days 11, 14 and 21, the positive predictive value was 89%, 93% and 92%. The negative predictive value was 28%, 40% and 54%. Conclusions. The predictive value of a single β-hCG measurement for pregnancy outcome after single blastocyst transfer increases between days 11 and 21 after OR. A single β-hCG measurement on day 14 may balance the accuracy of prediction and the necessity of an early reassuring test.