Plasma Microrna Profiling in Overweight and Obese Pregnant Women: An Exploratory Pooled-Sample Study

Background: Maternal overweight and obesity are associated with metabolic, vascular, and obstetric complications. Circulating microRNAs (miRNAs) are stable in plasma and may reflect obesity-related molecular alterations during pregnancy. Aim: To compare plasma miRNA expression profiles between normal-weight and overweight/obese pregnant women. Methods: The study included 50 pregnant women: 25 with normal weight and 25 with overweight/obesity. RNA was isolated from individual plasma samples and combined into one pooled RNA sample per study group. The pooled samples were analyzed in technical triplicate using a 96-well miRCURY LNA PCR panel containing 84 target miRNA assays and quality-control/reference assays. Results: Seventeen target miRNAs met the predefined >2-fold higher-expression threshold and 15 met the <0.5-fold threshold in the over-weight/obese pool. miR-21-5p was the only target miRNA that met both the predefined twofold magnitude criterion and the nominal p < 0.05 threshold (fold change = 2.58; p = 0.030266). Conclusion: The pooled-sample analysis identifies miR-21-5p as an exploratory candidate signal associated with maternal overweight/obesity. Individual-sample testing and validation in larger independent cohorts are required before biomarker performance or clinical utility can be established.