Molecular Mechanisms of Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is defined by the occurrence of two or more consecutive miscarriages and affects up to 5% of couples worldwide. At a molecular level, RPL arises from a complex interplay of genetic, epigenetic and immunological factors that impair key processes in early gestation. Central to healthy pregnancy are the invasion and migration of trophoblast cells into the maternal decidua, regulated by a network of growth factors, cytokines and non-coding RNAs. Disruption of placental angiogenesis, aberrant immune-cell polarisation at the maternal–foetal interface, and dysregulated microRNA expression have all been implicated in recurrent loss. These molecular insights have underscored the importance of balanced signalling through pathways such as VEGF–VEGFR and p38 MAPK, proper epithelial-mesenchymal transition (EMT) of trophoblasts, and tight regulation of inflammatory mediators. Advances in high-throughput sequencing, functional genomics and animal modelling are now driving the development of diagnostic biomarkers and targeted interventions, with the ultimate goal of improving outcomes for those at risk of RPL.

Research from Nature Portfolio

Seminal work has demonstrated that elevated levels of a specific microRNA in the placenta directly downregulate vascular endothelial growth factor (VEGF), a master regulator of angiogenesis. In vitro studies established that overexpression of this microRNA inhibits endothelial cell proliferation, migration and tube formation, while in vivo experiments confirmed that dysregulated microRNA expression reduces placental vascular density and increases rates of pregnancy loss. These findings provide a mechanistic framework linking microRNA-mediated suppression of angiogenic signalling to the pathogenesis of recurrent pregnancy loss.

Molecular Mechanisms of Recurrent Pregnancy Loss publication trend

The graph below shows the total number of articles in molecular mechanisms of recurrent pregnancy loss across all publications each year (not limited to Nature Index journals).

Technical terms

MicroRNA: A short non-coding RNA molecule that post-transcriptionally regulates gene expression by binding to complementary sequences in target mRNAs.

Trophoblast: Placental cells that invade the maternal decidua to establish nutrient and gas exchange between mother and embryo.

Epithelial-mesenchymal transition (EMT): A biological process during which epithelial cells acquire mesenchymal traits, enhancing motility and invasiveness.

Angiogenesis: The formation of new blood vessels from pre-existing vasculature, essential for placental development and foetal growth.

Exosome: A small extracellular vesicle released by cells that transports proteins, lipids and RNAs for intercellular communication.

References

1. MicroRNA-16 inhibits feto-maternal angiogenesis and causes recurrent spontaneous abortion by targeting vascular endothelial growth factor. Scientific Reports (2016).
2. First-Trimester Screening for Miscarriage or Stillbirth—Prediction Model Based on MicroRNA Biomarkers. International Journal of Molecular Sciences (2023).
3. T Cell Subsets and the Expression of Related MicroRNAs in Patients with Recurrent Early Pregnancy Loss. Mediators of Inflammation (2023).
4. Exosome‐delivered miR‐410‐3p reverses epithelial‐mesenchymal transition, migration and invasion of trophoblasts in spontaneous abortion. Journal of Cellular and Molecular Medicine (2024).