Antiphospholipid (AN-te-fos-fo-LIP-id) syndrome occurs when your immune system attacks some of the normal proteins in your blood. It can cause blood clots in your arteries or veins. And it can cause pregnancy complications, such as miscarriage and stillbirth.
Blood clots in your leg veins cause a condition known as deep vein thrombosis (DVT). Damage from blood clots in your organs, such as your kidneys, lungs or brain, depends on the extent and location of the clot. For instance, a clot in your brain can cause a stroke.
There's no cure for antiphospholipid syndrome, but medications can reduce your risk of blood clots.