Abstract
Fetal growth restriction (FGR) is a condition where the fetus does not reach its genetically predetermined size, affecting 1 in 10 pregnancies and contributing to up to 50% of all stillbirths before 34 weeks of gestation. Current diagnostic methods primarily involve ultrasound and Doppler assessments, yet there is growing interest in identifying biomarkers for early diagnosis and improved management. This systematic review examined the role of microRNAs (miRNAs) in the pathogenesis of FGR, focusing on their potential as non-invasive biomarkers. MicroRNAs are small, non-coding RNAs that regulate gene expression. This review systematically assessed studies investigating the differential expression of miRNAs in maternal blood, serum, and plasma samples from FGR-affected pregnancies. A total of nine studies met the inclusion criteria, which showed the differential expression of a total of 48 miRNAs. miR-16-5p was consistently upregulated in multiple studies and trimesters. miR-590-3p and miR-206 were consistently upregulated in multiple trimesters. The common gene targets of these miRNAs are VEGF, PIGF, and MMP9. The downregulation of these genes contributes to impaired angiogenesis, trophoblast invasion, placental function, and fetal growth.