Because automated blood cell counters are now widely used in many clinical settings, an assessment of hemoglobin concentration or hematocrit is invariably accompanied by a platelet count. Thus many asymptomatic pregnant women are being screened for thrombocytopenia. The objective of a good screening program is to reduce morbidity and mortality and thereby improve the quality of life; criteria for the evaluation of pro- posed or ongoing screening programs are well established. However, the screening of pregnant women for thrombocytopenia seems to have been both technologically mandated and passively accepted. Therefore we systematically evaluated the current de facto screening of asymptomatic pregnant patients for thrombocytopenia in the context of well-explained, desirable characteristics for a successful screening program. We conclude that screening for thrombocytopenia in pregnancy fails to meet established criteria, may actually be harmful (by placing unaffected fetuses of thrombocytopenic women, and the women themselves, at risk from invasive procedures), and should therefore be discontinued.