**8. Conclusions**

Nowadays, we have gained new insights into the pathogenesis and management of obstetric APS. Contrary to what was first thought, aPLs determine pregnancy morbidity with both inflammatory and non-inflammatory mechanisms. These findings have led to a better understanding of the different features of obstetric APS. While, inadequate invasion of maternal spiral arteries by the extravillous cytotrophoblast leads to early miscarriage, a lack of transformation of these arteries along with activation of the complement and the coagulation cascade is responsible for late pregnancy loss and preeclampsia. APS pregnancies should be classified into low, medium and high-risk classes based on clinical and laboratory features. Depending on the risk class, the most appropriate therapy must then be selected. Although studies have shown that intervention at the first signs of placental insufficiency can improve the pregnancy outcome, it is advisable to initiate the most appropriate therapy based on the risk class immediately at the beginning of pregnancy. It should be remembered that invasion of the trophoblast into the maternal spiral arteries occurs in the very early stages of placentation and adequate anchorage of the placenta is essential for the development of the pregnancy. Therefore, we need to start most appropriate therapy as soon as possible to facilitate a favorable pregnancy outcome.
