Early decrease in circulating miR-21 correlates with preeclampsia occurrence and Outcomes: A retrospective study

Preeclampsia (PE) is a major cause of maternal and neonatal illness and death. Early pregnancy screening poorly predicts its onset and severity. Circulating microRNAs, especially miR-21, are promising biomarkers. This study examined whether lower first-trimester miR-21 levels relate to PE development, severity, and outcomes. A retrospective analysis was performed involving 148 women diagnosed with PE and 95 normotensive pregnant individuals as controls. Blood plasma samples were collected at 11 to 13 + 6 weeks of gestation and again at the point of clinical PE diagnosis. qRT-PCR was used to assess miR-21 expression. Medical records provided data on blood pressure measurements, proteinuria over 24 h, and perinatal outcomes. miR-21 expression in the first trimester was significantly reduced in those who later developed PE compared to the control group (p < 0.001). The ROC analysis indicated a fair predictive value (AUC = 0.75). Within the PE cohort, those with severe disease exhibited significantly lower early miR-21 levels than those with mild disease (p < 0.001). Inverse correlations were found between miR-21 levels and systolic blood pressure, diastolic blood pressure, and proteinuria. Notably, individuals with poor pregnancy outcomes also had lower miR-21 levels, with first-trimester levels offering greater prognostic insight (AUC = 0.77) compared to levels measured at diagnosis (AUC = 0.71). Reduced circulating miR-21 levels in early pregnancy are associated with increased risk, greater severity, and poorer outcomes in PE. Early measurement of miR-21 may serve as a clinically useful biomarker for risk prediction and individualized management.