This chapter provides a basic understanding of pre-eclampsia (PET) and a detailed understanding of hematological complications and their management. Current hypothesis is that PET is a two-stage disease: the first stage is reduced placental perfusion and the second stage is the maternal response to this with endothelial cell activation. Maternal constitutional factors that have been proposed to act as inductors of the maternal syndrome of PET, include several dietary factors, metabolic conditions, obesity, metabolic syndrome, folic acid and hyperhomocysteinemia, hyperlipidemia, maternal vitamin D deficiency, and thrombophilia. Despite PET and fetal growth restriction (FGR) occurring only in pregnancy, they have been shown to have long-term consequences for both mother and fetus. Hematological complications of PET include thrombocytopenia, disseminated intravascular coagulation (DIC), HELLP syndrome, and massive bleeding after placental abruption. Differential diagnosis includes microangiopathic hemolytic anemias (MAHA): thrombotic thrombocytopenic purpura, TTP, hemolytic uremic syndrome (HUS), and acute fatty liver of pregnancy (AFLP).