Relaxin and Placental Volume in Placenta Accreta Spectrum

The primary source of relaxin in pregnancy is the corpus luteum, but it is also produced in other tissues, such as the decidua and placenta. Importantly, relaxin's pleiotropic effects include endothelial-dependent vasodilation, extracellular matrix remodeling, and potential contributions to placental development. These properties make relaxin a molecule of interest in the context of PAS disorders, where abnormal placental invasion may reflect disruptions in vascular and extracellular matrix regulation. Additionally, recent findings have indicated altered expression of relaxin, its receptor RXFP1, and insulin-like peptide 4 (INSL4) in PAS cases, suggesting potential roles in its pathogenesis.

Placental volume, assessed through imaging modalities, has been explored as a potential biomarker for abnormal placental development, including PAS. Studies have demonstrated that larger placental volumes may be associated with invasive placentation, suggesting a correlation between placental growth patterns and PAS severity.