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.