Do antiphospholipid antibodies cause preeclampsia and HELLP syndrome?

Antiphospholipid syndrome (APS) is associated with adverse pregnancy outcomes including preeclampsia, recurrent early pregnancy loss, fetal death, and intrauterine growth restriction. Approximately one third of women with APS will develop preeclampsia during pregnancy. The association between antiphospholipid antibodies (aPL) in the absence of the clinical syndrome and preeclampsia is less clear, and a causal relationship has not yet been proven. Testing for aPL should be considered in women with early-onset (< 34 weeks) severe preeclampsia, eclampsia, or HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, especially when additional clinical features of APS are present. Prospective testing for aPL in women at risk for preeclampsia is not recommended. Current evidence does not justify inclusion of preeclampsia as a major criterion for APS, but preeclampsia could reasonably be included as a secondary or minor criterion in diagnosis when a patient has other clinical features of APS.