Universal First Trimester Screening Biomarkers for Diagnosis of Preeclampsia and Placenta Accreta Spectrum

Background: Disruptions in epigenetic mechanisms regulating placentation, particularly imbal-ances in the levels of small non-coding RNAs, contribute to various pregnancy complications, including preeclampsia (PE) and placenta accreta spectrum (PAS). Given that abnormal trophoblast differentiation, invasiveness, and angiogenesis—reduced in PE and excessive in PAS—are central to the pathogenesis of these conditions, this study aims to identify universal circulating piRNAs and their targets. Methods: Small RNA deep sequencing, quantitative reverse transcription combined with real-time polymerase chain reaction, magnetic bead-based multiplex immunoassay, ELISA, and Western blotting were employed to quantify circulating piRNAs and proteins in the blood serum of pregnant women during the 11th–14th weeks of gestation. Results: Statistically significant negative correlations were identified between PE- and PAS-associated piRNAs (hsa_piR_019122, hsa_piR_020497, hsa_piR_019949, piR_019675) and sev-eral molecules, including Endoglin, IL-18, VEGF-A, VEGF-C, Angiopoietin-2, sFASL, HB-EGF, TGFα, and Clusterin. These molecules are involved in processes such as angiogenesis, inflam-mation, epithelial-mesenchymal transition, cell proliferation, adhesion, and apoptosis. A first-trimester pregnancy screening algorithm was developed using logistic regression models based on Clusterin concentration and the levels of hsa_piR_020497, hsa_piR_019949, piR_019675, and hsa_piR_019122. Conclusions: The proposed screening tool for early pregnancy monitoring may enable the prediction of PE or PAS in the first trimester, allowing timely interventions to reduce maternal and perinatal morbidity and mortality.