Therefore, this study investigated the therapeutic effects of hypoxia-preconditioned HF-MSC-derived exosomes (Hy-Exos) on UC and examined the differences in Hy-Exos components compared with HF-MSC-derived exosomes (Exos) to further explore the relationship between Hy-Exos and the PI3K/AKT/mTOR signaling pathway and mitophagy. Here, AKT1 is linked to hydrops fetalis.