antiphosphlolipid disorders

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antiphosphlolipid disorders

The Antiphospholipid Syndrome

Vol.1 No.4

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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.

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