Effective screening for the development of early onset preeclampsia (PE) can be provided in the first-trimester of pregnancy. Screening by a combination of maternal risk factors, uterine artery Doppler, mean arterial pressure, maternal serum pregnancy-associated plasma protein-A, and placental growth factor can identify about 95% of cases of early onset PE for a false-positive rate of 10%.

Changes in maternal plasma proteins during pregnancy are now well documented. These changes may be quantitative, as seen in the electrophoretically separated fractions of serum and in the various binding globulins; or they may be represented by the appearance of a protein which is present only in the serum of pregnant women. These include the placental isoenzyme of alkaline phosphatase, oxytoci...