Moreover, PBX1 knockdown significantly reduced the percentage of HF-MSCs in the S phase from 12.53% ± 0.782% to 7.39% ± 1.01% (P < 0.05) and the PIs from 20.34 ± 0.99 to 12.50 ± 1.05 (P < 0.05; Fig. 3b–d). This evidence concerns the gene PBX1 and hydrops fetalis.