IGF2 and hydrops fetalis: C, Chow; E2, Estradiol; FSH, follicle-stimulating hormone; HF, high fat; H&E, hematoxylin and eosin; HPG, hypothalamic–pituitary–gonadal; Igf2, insulin-like growth factor 2; Igf2r, insulin-like growth factor 2 receptor; LH, luteinizing hormone; PND, postnatal day; SD, Sprague-Dawley.