Obstetric and thrombotic outcomes among pregnant patients with myeloproliferative neoplasms: a propensity score matched real-world analysis.

Pregnancies complicated by BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are associated with increased maternal and thrombotic risk; however, large real-world comparative data remain limited. We performed a multicenter retrospective propensity score-matched cohort study using the TriNetX database to evaluate maternal, obstetric, and thrombotic outcomes among pregnant patients with MPN compared with matched non-MPN controls. Baseline demographics, comorbidities, and antithrombotic medication use were balanced after matching (standardized mean difference < 0.1). Among 4,467,127 pregnancies, 4,563 patients had MPN, most commonly essential thrombocytosis (85%). Compared with matched controls, MPN pregnancies had significantly higher all-cause mortality (1.1% vs. 0.2%; hazard ratio [HR] 5.4, 95% CI 2.7-10.8), gestational hypertension (11.1% vs. 7.8%; HR 1.3, 95% CI 1.1-1.5), preeclampsia/eclampsia (10.4% vs. 5.3%; HR 1.8, 95% CI 1.6-2.1), preterm labor (6.1% vs. 3.7%; HR 1.5, 95% CI 1.2-1.8), intrauterine growth restriction (7.3% vs. 5.1%; HR 1.3, 95% CI 1.1-1.7), postpartum hemorrhage (5.5% vs. 3.8%; HR 1.3, 95% CI 1.1-1.6), and venous thromboembolism (2.7% vs. 0.7%; HR 3.2, 95% CI 2.2-4.6). Arterial thrombotic events were not significantly different between groups. Pregnancies in patients with MPN are associated with significantly increased maternal, obstetric, and venous thrombotic complications, highlighting the need for multidisciplinary management and individualized thromboprophylaxis strategies.