MAPK3 and hydrops fetalis: Based on these results, we speculated that circACTN1 and circITGA6 are essential and beneficial for gHFSCs growth and HF development in YRDWG via the chi-circACTN1-miR-671-5p-MAPK3/COL13A1 axis, and chi-circITGA6-miR-18a-5p-FGF1 /MAP3K1 axis.