We observed that 0.05 μm HF could completely inhibit COL1A1 expression in CAF2 at 8 h after treatment (Figure S10B, Supporting Information), so we treated CAF2 with 0.05 μm HF for 8 h and 12 h, and found that HF inhibited collagen contraction using a cell contraction assay (Figure 4B). This evidence concerns the gene COL1A1 and hydrops fetalis.