The antiphospholipid syndrome (APS) is associated with pregnancy morbidity and vascular thrombosis in the presence of circulating antiphospholipid (aPL) antibodies. Clinical manifestations of aPL antibodies represent a spectrum (asymptomatic, pregnancy events, vascular events, or both pregnancy and vascular events), and APS should not be considered a single disease with a predictable outcome. Patients with aPL antibodies are at increased risk of vascular thrombotic events during pregnancy, the postpartum period, and even during long-term follow-up after an APS-related pregnancy event. Therefore, the purpose of this paper is to review the relation between APS-related pregnancy morbidity and vascular thrombosis, and to address the importance of prophylactic therapy during and after APS pregnancies to prevent maternal thrombotic complications. During pregnancy, low-dose aspirin (LDA) should be considered for all patients with aPL antibodies and heparin should be added to LDA in patients fulfilling the Sapporo criteria for definite APS. During delivery, especially with caesarian section, periods without anticoagulation should be kept to an absolute minimum. Some data suggest that LDA might be effective against future non-gravid vascular thrombosis in patients with APS and a history of only pregnancy morbidity.