Obstetric antiphospholipid syndrome (APS) seems to be a clinical subset of classical APS, for which the search for new markers is still challenging. Soluble CD146 (sCD146) constitutes a circulating endothelial biomarker. sCD146 is involved in the inflammatory response by promoting monocyte transmigration and displays chemotactic and angiogenic properties on endothelial cells. Its detection in human sera reveals physiological variations related to age and sex. A wide variation of sCD146 has been reported in several conditions. In particular, sCD146 levels are significantly higher in women presenting a history of recurrent fetal losses.