Early-Onset Severe Preeclampsia as an Independent Predictor of New-Onset Maternal Arrhythmia During Pregnancy: A Retrospective Cohort Study.

Background Early-onset severe preeclampsia (EOSPE) is characterized by marked vascular injury, systemic inflammation, and acute hemodynamic stress. However, its independent association with newly occurring maternal arrhythmias during pregnancy has not been well established. Objective To evaluate whether EOSPE independently increases the risk of new-onset maternal arrhythmia using propensity score matching. Methods We conducted a retrospective cohort study using the TriNetX database from 2015 to 2024. Pregnant individuals aged 18 to 45 years were included. EOSPE was defined as preeclampsia with severe features occurring before 34 weeks of gestation according to American College of Obstetricians and Gynecologists criteria. The primary outcome was new-onset maternal arrhythmia, including supraventricular tachycardia, atrial fibrillation or flutter, ventricular arrhythmias, clinically significant ectopy, or conduction disorders occurring during pregnancy or within six weeks postpartum. Patients with prior arrhythmia or structural heart disease were excluded. After applying inclusion and exclusion criteria, 742 EOSPE patients were matched 1:1 with controls without hypertensive disorders of pregnancy. Matching variables included age, race, body mass index, chronic hypertension, diabetes mellitus, chronic kidney disease, obesity, tobacco use, and prior adverse pregnancy history. Statistical analyses included conditional logistic regression, multivariable adjustment, Cox proportional hazards modeling, and subgroup interaction testing. Results Following matching, baseline characteristics were well balanced with standardized mean differences below 0.08. New-onset maternal arrhythmia occurred in 6.2% (46/742) of EOSPE patients compared with 2.4% (18/742) of controls, corresponding to an absolute risk difference of 3.8%. EOSPE was associated with increased odds of arrhythmia (odds ratio 2.68, 95% confidence interval 1.53 to 4.70; p < 0.001), which remained significant after adjustment (adjusted odds ratio 2.49, 95% confidence interval 1.39 to 4.45; p = 0.002). Time-to-event analysis demonstrated a higher hazard of arrhythmia (hazard ratio 2.41, 95% confidence interval 1.38 to 4.20; log-rank p < 0.001). Subtype analysis showed increased rates of supraventricular tachycardia (3.5% vs. 1.3%) and atrial fibrillation or flutter (1.5% vs. 0.4%) in the EOSPE group. Conclusions EOSPE is independently associated with a significantly increased risk of new-onset maternal arrhythmia during pregnancy and the postpartum period. These findings support closer cardiovascular monitoring in this high-risk population.