TGFB1 and placenta praevia: Trauma can destroy the basal layer of the endometrium or the myometrium, and activate TGF-β1/Smad pathway and inflammatory factor (Bai et al., 2020; Leung et al., 2021), which leads to an abnormal mother–fetus interface, resulting in placenta previa or placenta accreta (Zhang et al., 2020).