The Antiphospholipid Syndrome

Vol.1 No.4 

back | home | register

by Sara Marder, M.D.

Instructor and Fellow in Maternal and Fetal Medicine

Department of Obstetrics and Gynecology 
Yale University School of Medicine 

Antiphospholipid Antibody Syndrome

There are many causes that have been linked to recurrent pregnancy loss. One of the less frequently seen associations is known as the antiphospholipid antibody syndrome.  
What are antiphospholipid antibodies?  
Under normal circumstances, antibodies are proteins made by your immune system to fight substances recognized as foreign by your body. Some examples of foreign substances are bacteria and viruses. Sometimes the body's own cells are recognized as foreign. In the antiphospholipid antibody syndrome the body recognizes phospholipids (part of a cell's membrane) as foreign and produces antibodies against them. Antibodies to phospholipids (antiphospholipid antibodies) can be found in the blood of some people with lupus, but they are also seen in people without any known illness. Lupus anticoagulant (LAC) and anticardiolipin antibody (ACA) are the two known antiphospholipid antibodies that are associated with recurrent pregnancy loss.  

What is the antiphospholipid antibody syndrome?  
Different physicians may use slightly different definitions to diagnose the antiphospholipid antibody syndrome. In general you need to have a positive blood test for either the lupus anticoagulant or the anticardiolipin antibody, on two separate occasions, at least eight weeks apart. In addition to the blood tests you must also have one the following criteria: A history of thrombosis (clots within the blood vessels), thrombocytopenia (low platelet count) or recurrent pregnancy loss. Several other manifestations may be seen, but not always, in patients with the antiphospholipid antibody syndrome which include skin, heart and nervous system abnormalities.  

What is the association between antiphospholipid antibodies and pregnancy loss?  
Among women with recurrent pregnancy losses antiphospholipid antibodies have reported to be present in 11%-22%. Lupus anticoagulant (LAC) and/or medium to high anticardiolipin antibodies (ACA) have been associated with first, second, and third trimester pregnancy losses. The association is even higher when the antiphospholipid antibody tests are persistently positive. Although it is unknown exactly how the antiphospholipid antibody syndrome adversely affects pregnancy, one theory is that it may cause blood clots. These blood clots, which can be microscopic, may occur in the blood vessels of the placenta. The placenta provides nourishment to the baby and any interruption in this process can be harmful to the pregnancy. The antiphospholipid syndrome may increase the risk of miscarriage, poor fetal growth, preeclampsia (high blood pressure during pregnancy), and stillbirth. It has yet to be proven but many researchers think the antiphospholipid antibody syndrome may exist in a state of remission or exacerbation similar to other diseases such as lupus or rheumatoid arthritis. This means you could have periods of times when the antibodies are not active.  
Who should be tested for antiphospholipid antibody syndrome 
Women who have had a history of recurrent pregnancy losses should be tested for antiphospholipid antibodies in addition to other routine tests. A history of unexplained poor fetal growth and or the early onset of severe preeclampsia (toxemia, also known as high blood pressure in pregnancy) or an unexplained placental abruption are indications for testing. A history of thrombosis (clots in the blood vessels), stroke, heart attack, thrombocytopenia (low platelet count), presence of other autoimmune disorders such as lupus, an abnormal VDRL, or PTT blood tests would suggest the need for testing.  
What is the treatment for the antiphospholipid syndrome in pregnancy? 
The drug of choice for treatment is Heparin, which is an injection to prevent blood from clotting. It is used in combination with "baby" (low dose) aspirin. In certain cases Prednisone and baby aspirin are used to treat the antiphospholipid antibody syndrome. All medications have side effects and the choice of therapy should be made after the risks and benefits of the treatments have been discussed between the physician and the patient. These pregnancies should be monitored closely by ultrasound every month to check on fetal growth and by antenatal testing (non-stress tests and biophysical profiles) weekly, beginning at 32 weeks gestation. Although there are a few reports of successful pregnancies without treatment, the majority of researchers have reported a 70%-75% success rate with treatment.

   Next Journal Article