Figure 4. Phosphatidylinositol-glycan biosynthesis class F (PIGF) concentrations across pregnancy.

PIGF was measured across pregnancy in 50 women who later developed preeclampsia (□) or 250 women who did not develop preeclampsia (◆). Between 15 and 22 weeks of pregnancy, values are significantly lower in women who later developed preeclampsia (p < 0.04). However, the ROC curve for these data had an area under the curve of 0.64, and if a cut off value was selected that resulted in a 20% false=positive rate, the accompanying sensitivity was 40%. In a population in which preeclampsia developed in 5% of pregnancy, the positive predictive value would be 9.5%.