We used our established model of dietary iron administration in rats (Huebner et al., 2018 (link), 2016 (link)). Nulliparous, 8-week old Long-Evans female rats (Envigo, Richmond IN) were randomly assigned to consume one of three diets ad libitum: the iron-sufficient (IS) diet (containing 100 ppm iron; TD.06016); the iron-deficient (ID) diet (containing 100 ppm iron from GD0.5–5 [TD.06016], 20 ppm iron from GD5–13.5 [TD.06013], and 2–6 ppm iron from GD13.5–20.5 [TD.80396]); or the iron-fortified (IF) diet (containing 500 ppm iron; TD.110880). Diet composition was based on AIN-76A (Huebner et al., 2018 (link), 2016 (link)), and diets were produced by Teklad-Envigo (Madison, WI). Rats consumed the assigned diet at least 2 weeks prior to and throughout pregnancy. Gestational day (GD) 0.5 was defined as the morning a vaginal plug was discovered. Litters containing <9 or >15 pups were excluded from analyses to eliminate extremes in iron distribution across litters within a treatment group. On GD20.5, following isoflurane overdose and maternal perfusion, maternal and fetal tissues were collected, flash frozen in liquid nitrogen, and stored at −80°C until further analysis. The Institutional Animal Care and Use Committee approved all protocols.