Double measurements of serum HCG concentration and its ratio may predict IVF outcome.

Serum human chorionic gonadotrophin (HCG) concentration is nearly always used to predict pregnancy but there is little data on the clinical utility of the ratio of HCG(21)/HCG(14) combined with double measurement of serum HCG. A total of 1762 cycles were retrospectively analysed for serum HCG concentration and ratio of HCG(21)/HCG(14) on days 14 and 21 after embryo transfer to determine whether the ratio combined with concentration is the optimal predictor of pregnancy. The medians of HCG concentration on days 14 and 21 combined with the ratio of HCG(21)/HCG(14) were calculated for non-viable, viable and heterotopic pregnancies. HCG concentrations of 290IU/l on day 14 and 2970IU/l on day 21 were regarded as the cut-off values to predict viable pregnancy, and values of 630 and 12,000IU/l, respectively, were regarded as the cut-off values to predict multiple pregnancy. The ratio of HCG(21)/HCG(14) in the viable pregnancy group was significantly higher than that in the non-viable pregnancy group (15.86 versus 5.27, P<0.0001). For heterotopic pregnancy, the ratio of HCG(21)/HCG(14) was 11.93. It was concluded that HCG concentration on days 14 and 21 combined with the ratio of HCG(21)/HCG(14) provides a useful predictor of pregnancy outcome. A ratio >15 may predict viable pregnancy.