Abnormalities in platelet antiglobulin tests in preeclamptic mothers and their neonates.

We prospectively studied 40 women with preeclampsia and 26 women with normal pregnancy for the presence of platelet-bound and circulating platelet-bindable immunoglobulin and complement. Although only 12 patients with preeclampsia had a platelet count less than 150,000/mm3, 36 of 40 demonstrated an abnormal direct antiglobulin test, compared with only three of 26 control subjects (p less than 10(-8]. An abnormal indirect test was also detected in 30 of 40 patients with preeclampsia compared with five of 26 healthy pregnant control women (p = 9.3 X 10(-6]. Abnormal antiglobulin tests persisted for 2 to 6 weeks after delivery. Although each neonate had a platelet count greater than 200,000/mm3 at the time of delivery, 10 of 18 had an abnormal direct antiglobulin test compared with one of 14 control subjects (p = 0.0049). The high frequency of abnormal platelet antiglobulin tests in women with preeclampsia and their neonates may indicate an immune cause of certain aspects of the syndrome or may reflect the extent of platelet activation.