Regardless of age, the effects of maternal metformin on Opa1 expression were found only in female offspring (main effect of maternal metformin, p < 0.05, Figure 4B,D), and there was an interaction effect of maternal HF diet and metformin on Opa1 expression in adult female offspring (p < 0.05, Figure 4D). Here, OPA1 is linked to hydrops fetalis.