PGF and preeclampsia: In the second meta-analysis the objective was to investigate the accuracy of serum biochemical markers (Pregnancy-Associated Plasma Protein-A (PAPP-A), human Chorionic Gonadotropin (hCG), Placental Growth Factor (PlGF), Placental Protein 13 (PP13) used in first trimester serum screening in predicting preeclampsia, small for gestational age (SGA) and preterm delivery [13].