Antiphospholipid antibody syndrome is a blood-clotting disorder that makes the blood clot too easily. This can lead to mild or severe blood-clotting complications, including miscarriage, serious pregnancy problems, stroke, heart problems, and blood clots in the legs or lungs.

Antiphospholipid antibody syndrome is caused by antibodies. The body normally makes antibodies that attack a dangerous substance in the body, like bacteria or a virus. Instead, antiphospholipid antibodies attack molecules that keep the blood from clotting too much. A person who has these antibodies and has had blood clots is said to have antiphospholipid antibody syndrome.

Antiphospholipid antibodies can be detected with a blood test. Once diagnosed, this condition is usually treated with blood-thinning medicine. Treatment and close monitoring are needed during pregnancy.