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 ≤ 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 ≤ 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.