HIF1A and hydrops fetalis: Instead, several publications have reported on reciprocal effects between the HIF, Notch, and TGFβ signaling pathways, and our current conclusion thus is that the observed upregulation of HIF1 and HIF2 in the current model leads to an imbalance between HIF, Notch, and TGFβ signaling homeostasis required for normal HF development.