Although the exact etiology of APS is still not clear, genetics is believed to play a key role in the development of the disease.
[5] Antiphospholipid syndrome often requires treatment with anticoagulant medication to reduce the risk of further episodes of thrombosis and improve the prognosis of pregnancy.
Antiphospholipid syndrome is known for causing arterial or venous blood clots, in any organ system, and pregnancy-related complications.
While blood clots and pregnancy complications are the most common and diagnostic symptoms associated with APS, other organs and body parts may be affected like platelet levels, heart, kidneys, brain, and skin.
[8] People experiencing a stroke can experience a variety of symptoms depending on what blood vessel in the brain is affected.
Symptoms include but are not limited to trouble speaking, loss of sensation, or weakness in one side of the face or body.
[6] Exogenous estrogen therapies, such as estrogen-based contraceptives, significantly increase the risk of developing blood clots for patients with APS.
[10] In pregnant people affected by APS, there is an increased risk of recurrent miscarriage, preterm birth, intrauterine growth restriction, pre-eclampsia, eclampsia.
[6] There are also associations between antiphospholipid antibodies and different neurologic manifestations[14] including headache,[15] migraine,[16] epilepsy,[17] and dementia[18] although more research is needed to prove that these symptoms are indicative of APS.
Annexin A5 forms a shield around negatively charged phospholipid molecules, which reduces the membrane's ability to participate in clotting.
[citation needed] The increased risks of recurrent miscarriage, intrauterine growth restriction and preterm birth by antiphospholipid antibodies, as supported by in vitro studies, include decreased trophoblast viability, syncytialization and invasion, deranged production of hormones and signalling molecules by trophoblasts, as well as activation of coagulation and complement pathways.
[12] The Sydney criteria requires one clinical (thrombosis or pregnancy related) manifestation and persistent presence of one or more APS antibody.
Based on this statement, Definite CAPS diagnosis requires:[26] Antiphospholipid antibody tests are either liquid-phase coagulation assays to detect lupus anticoagulant or solid phase ELISA (enzyme-linked immunosorbent assay) to detect anti-cardiolipin antibodies and β2 glycoprotein 1.
A patient with lupus anticoagulant antibodies on initial screening will typically have been found to have a prolonged partial thromboplastin time (PTT) that does not correct in an 80:20 mixture with normal human plasma (50:50 mixes with normal plasma are insensitive to all but the highest antibody levels).
The Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis no longer recommends the kaolin clotting time, dilute thromboplastin time, and Taipan/Ecarin snake venom based assays due to implementation issues from a variety of factors.
[23] Also, patients who have certain antiphospholipid antibodies may have false positive VDRL test, which aims to detect a syphilis infection.
[28] Women with recurrent miscarriages are often advised to take aspirin and to start low molecular weight heparin treatment after missing a menstrual cycle.
[6] Factors associated with developing antiphospholipid syndrome include: In a study of 1000 patients, only 12.7% were diagnosed after the age of 50.
[citation needed] According to a 2006 Sydney consensus statement,[12] it is advisable to classify APS into one of the following categories for research purposes: