First trimester maternal serum placental protein 13 for the prediction of pre-eclampsia in women with a priori high risk.

OBJECTIVE To evaluate whether first trimester maternal serum PP13 can predict pre-eclampsia among women with a priori high risk. METHOD This was a nested case-control study. Women less than 14 weeks' gestation at increased risk of developing pre-eclampsia were recruited. Venous blood samples were assayed for PP13 using enzyme-linked immunosorbent assay. PP13 multiples of median (MoM) were calculated and adjusted for body mass index, ethnicity, smoking, maternal age and parity. For each case of pre-eclampsia (n = 42), five controls were randomly selected. PP13 levels were compared between women who developed pre-eclampsia and controls using the Wilcoxon rank sum test. Sensitivity and false-positive rates were derived from receiver operating characteristic curves. RESULTS Women who developed pre-eclampsia had significantly lower (P < 0.001) PP13 MoMs compared with controls. PP13 MoMs for controls and pre-eclampsia cases were 1.0 (range 0.0-10.0) and 0.4 (range 0.0-7.0), respectively (P < 0.001). At a MoM cutoff of 0.53, for a false-positive rate of 10%, sensitivity was 50% for pre-eclampsia at term (>37 weeks), 62% for preterm pre-eclampsia (<37 weeks) and 71% for early-onset pre-eclampsia (<34 weeks). CONCLUSION First trimester PP13 can predict pre-eclampsia in women at increased a priori risk and predicts early-onset better than late-onset disease.