Mild thrombocytopenia indicating maternal organ damage in pre‐eclampsia: a cross‐sectional study

BACKGROUND: Currently, there is a disagreement between guidelines regarding platelet count cut-off values as a sign of maternal organ damage in pre-eclampsia; the American College of Obstetricians and Gynecologists guidelines state a cut-off value of < 100 × 10(9)/L; however, the International Society for the Study of Hypertension in Pregnancy guidelines specify a cut-off of < 150 × 10(9)/L. We evaluated the effect of mild thrombocytopenia: platelet count < 150 × 10(9)/L and ≥ 100 × 10(9)/L on clinical features of pre-eclampsia to examine whether mild thrombocytopenia reflects maternal organ damage in pre-eclampsia. METHODS: A total of 264 women were enrolled in this study. Participants were divided into three groups based on platelet count levels at delivery: normal, ≥ 150 × 10(9)/L; mild thrombocytopenia, < 150 × 10(9)/L and ≥ 100 × 10(9)/L; and severe thrombocytopenia, < 100 × 10(9)/L. Risk of severe hypertension, utero-placental dysfunction, maternal organ damage, preterm delivery, and neonatal intensive care unit admission were analyzed based on platelet count levels. Estimated relative risk was calculated with a Poisson regression analysis with a robust error. RESULTS: Platelet counts indicated normal levels in 189 patients, mild thrombocytopenia in 51 patients, and severe thrombocytopenia in 24 patients. The estimated relative risks of severe thrombocytopenia were 4.46 [95 % confidence interval, 2.59–7.68] for maternal organ damage except for thrombocytopenia, 1.61 [1.06–2.45] for preterm delivery < 34 gestational weeks, and 1.35 [1.06–1.73] for neonatal intensive care unit admission. On the other hand, the estimated relative risks of mild thrombocytopenia were 0.97 [0.41–2.26] for maternal organ damage except for thrombocytopenia, 0.91 [0.62–1.35] for preterm delivery < 34 gestational weeks, and 0.97 [0.76–1.24] for neonatal intensive care unit admission. CONCLUSIONS: Mild thrombocytopenia was not associated with severe features of pre-eclampsia and would not be suitable as a sign of maternal organ damage.