The pregnancy physiologically navigates, sort of speaking, the hematopoietic system in the direction of hypercoagulabile state, which grows stronger throughout the pregnancy and reaches its maximum at the time of the delivery. These changes are considered to be the protection of the pregnant woman during puerperium, but if over-emphasized, they could lead to complications in both mother and the fetus. The main hypothesis of pathophysiology of these problems, during pregnancy, is based on the events of forming the blood vessels between the placenta and the uterus. During the forming of placental circulation, as a result of non-adequate placentation and placental vascular thrombosis, certain secondary reactions may be manifested, such as: placental abruption, hypoxia and hypoxemia of the fetus, which result as fetal growth restriction. These states may be consequences of congenital or acquired thrombophilia. The therapy advised to these women varies, but there are no absolute evidences that it is obligatory. Clinical experience suggests that the use of aspirin, in the state of antiphospholipid syndrome, leads to better results, considering both the mother and the fetus.