Paired human chorionic gonadotrophin determinations for the prediction of pregnancy outcome in assisted reproduction

The aim of this study was to determine the prognostic value of single and paired measurements of serum concentrations of human chorionic gonadotrophin (HCG) for successful pregnancy following in-vitro fertilization (IVF) and tubal embryo transfer (TET). We analysed serum HCG concentrations 15 and 22 days after IVF or TET in 198 conception cycles. Cut-off values of serum HCG were determined by a receiver operating characteristic (ROC) curve. On the basis of single HCG samples on day 15 (HCG(15)) after transfer, using a cut-off value of HCG(15) = 150 mIU/ml, the sensitivity was 71% and the specificity was 77%. The positive predictive value (HCG(15) greater than or equal to 150 mIU/ml indicating a normal pregnancy) was 89%, while the negative predictive rate (HCG(15) <150 mIU/ml indicating an abnormal pregnancy) was 51%. Patients with HCG(15) <150 mIU/ml but HCG(22)/HCG(15) ratio greater than or equal to 15, still had a 90% chance of normal pregnancy. However, in patients with HCG(15) <150 mIU/ml and an HCG(22)/HCG(15) ratio <15, there was an 84% chance of an abnormal pregnancy. We conclude that a single HCG(15) determination combined with the ratio of HCG(22) to HCG(15) has a higher diagnostic accuracy for prediction of pregnancy outcome than either analysis alone.