Anti-Cardiolipin Antibody (ACA)

Definition - What does Anti-Cardiolipin Antibody (ACA) mean?

Anti-cardiolipin antibody (ACA) is a type of antiphospholipid antibody (a blood protein) directed against the fat-like component of the mitochondrial cell membrane called cardiolipin. Mitochondria are cell organelles that serve as a source of energy for the cell. The ACA can be found in several conditions such as antiphospholipid syndrome, syphilis, spontaneous abortions, and lupus.

Antiphospholipid syndrome (APS) is a condition in which antibodies that normally function to protect us from offending agents, start attacking the body's own tissues - phospholipids in this case. Women with APS and ACA are prone to recurrent miscarriages.

FertilitySmarts explains Anti-Cardiolipin Antibody (ACA)

The presence of anticardiolipin antibodies increases the risk of blood clots, which can form in both arteries and veins, giving rise to conditions like stroke and deep vein thrombosis (DVT). If women with ACA get pregnant, these blood clots can also affect placental vessels, cutting off the blood supply to the uterus and baby. This deprives the baby of the required nutrition and oxygen, making it impossible for it to survive inside the uterus.

There are three different types of ACA, including IgG, IgM, and IgA (Ig is the short form for immunoglobulin, which means antibody). Among these, the presence of IgM ACA more strongly predicts the occurrence of recurrent miscarriages and is a better indicator of pregnancy outcome than other types of antibodies. The presence of ACA cuts the chances of live birth rates by 36% to 48%. All the types of ACA are detected by a blood test called ELISA (enzyme-linked immunosorbent assay).

Women with unexplained repeated miscarriages are often found to have higher levels of ACA. APS is thought to account for around 30% of infertility cases. Detection of ACA, however, does not necessarily indicate APS. People with autoimmune diseases like lupus also test positive for ACA.

Antibodies like ACA may also be one of the potential causes of IVF failure.

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