SFRP2 and hydrops fetalis: These findings expand the regulatory mechanism of miR-218–5p beyond the previously reported SFRP2-Wnt/β-catenin axis, indicating involvement of multiple HF-related pathways, such as Wnt/β-catenin [56], MAPK [57], PI3K-Akt [58], and JAK-STAT signaling pathway [59].