Is there an association between platelet count during the first trimester and preeclampsia or other obstetric complications later in pregnancy?

OBJECTIVE: To examine whether an association exists between platelet (PLT) count in the first trimester of pregnancy and the risk for hypertensive disorders or other obstetric complications. METHODS: The study population included all registered births with available PLT count from the first trimester of pregnancy during 2000-2010. Thrombocytopenia was defined as PLT count below 100,000/µL. A comparison was performed between women with and without thrombocytopenia. Multiple logistic regression models were used to control for confounders. RESULTS: The study population included 33,890 deliveries; of these, 119 (0.35%) were with thrombocytopenia. Women with thrombocytopenia had significantly higher rates of preterm delivery (16.0% vs. 9.4%; p = 0.015). There was no significant difference between the groups regarding hypertensive disorders. CONCLUSIONS: Hypertensive disorders cannot be predicted based on PLT count during the first trimester of pregnancy. Nevertheless, thrombocytopenia during the first trimester is a risk factor for preterm delivery.