Serum tumor necrosis factor-α level and uterine artery Doppler indices at 11-13 weeks' gestation for preeclampsia screening in low-risk pregnancies: a prospective observational study.

Preeclampsia affects 1-2% of human pregnancies with no effective screening test. Studies have found some association between cytokines/other biomarkers and the later onset of preeclampsia. The challenge has been to find indicators with sufficient positive predictive value.