METTL3 and hydrops fetalis: Compared with the HF group (Figure 7A–D), mettl3 expression was significantly elevated, whereas fto and Alk B homolog 5 (alkbh5) levels were reduced in the HF-RES group (p < 0.05), with no significant difference detected in YTH N6-methyladenosine RNA binding protein 2 (ythdf2) expression (p > 0.05).