Antiphospholipid syndrome and pregnancy—a hematologic perspective

A state-of-the-art lecture entitled "APS and pregnancy: a haematologic perspective" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2025. Antiphospholipid syndrome (APS) is a multisystem autoimmune disorder associated with thrombotic and obstetric complications, which can often be difficult to diagnose and has limited treatment options. During pregnancy, APS presents a particularly complex set of issues with a high risk of thrombosis and adverse pregnancy-related outcomes. Since the initial description of APS by Graham Hughes et al in 1983, there have been many advancements in understanding of disease mechanisms, disease-defining criteria, and patient outcomes including pregnancy outcomes. However, there is still need for improvement, especially regarding risk stratification and optimal management to enhance pregnancy-related outcomes in APS. With few novel treatments are on the horizon, it is a clear reminder of the challenges involved in conducting clinical research during pregnancy. In this review, we will focus on a hematologic perspective of APS management relating to pregnancy, including discussion on prepregnancy counseling. There will be more of a focus on late adverse pregnancy outcomes and managing thrombosis-related issues and less emphasis on earlier pregnancy-related issues, such as recurrent miscarriage since this is more aligned with obstetric perspectives. Finally, we summarize relevant new data on this topic presented during the 2025 ISTH Congress.