First‐trimester screening biochemical markers (free beta‐subunit human chorionic gonadotropin, pregnancy‐associated plasma protein‐A) and risk of early fetal loss

Aim The aim of this work was to assess the risk of early fetal loss (first trimester of pregnancy, 8–13 weeks of gestation) using the results of first-trimester screening (FTS) biochemical markers independently and combined. Methods FTS results of 152 women who suffered early fetal loss were compared to a control group of 150 women with normal pregnancy outcomes. FTS biochemical markers were measured with a Delfia Xpress 6000 analyzer and biochemical risks for Down's and Edward's syndromes were calculated using Prenatal-Lifecycle version 3.0 software. Marker levels were standardized by calculating the gestational-specific multiple of the medians (MoM), further adjusted by maternal age, maternal weight, cigarette consumption and pre-existing type 1 diabetes mellitus. Receiver–operator curves were built to evaluate each marker and its combination. Results Our results show that values of biochemical risk of t21 of more than 1 in 310 have a poor sensitivity to predict early fetal loss (31.4%) with a positive predictive value (PPV) for fetal loss of 67.7%. Values of pregnancy-associated plasma protein A (PAPP-A) MoM of less than 0.48 show a sensitivity of 62.1% and a PPV of 84.5% for early fetal loss; whereas for free β-human chorionic gonadotropin, values of MoM of less than 0.44 have a sensitivity of 66.4% with a PPV of 85.3%. A novel algorithm, consisting in the multiplication of both markers, shows for values of less than 0.48 a sensitivity of 83.1%, a specificity of 78.7% and a PPV of 77.1%. Conclusion Combined analysis of PAPP-A and free β-hCG appears to be a potential candidate to predict early fetal loss.