The aim of this study was to investigate certain parameters regarding the maternal-fetal outcomes in a diet-induced obesity model. Obese, glucose-intolerant females who were exposed to a high-fat diet prior to pregnancy had lower placental efficiency and lower birth weight pups compared to the controls. Simple linear regression analyses showed that maternal obesity disrupts the proportionality between maternal and fetal outcomes during pregnancy. Maternal obesity is correlated with fetal outcomes, perhaps because of problems with hormonal signaling and exacerbation of inflammation in the maternal metabolic environment. The maternal obese phenotype altered the thickness of the placental layer, the transport of fatty acids, and the expression of growth factors. For example, lower expression of epidermal growth factor receptor (EGFR) mRNA in the obesity-prone group may have contributed to the rupture of the placental layers, leading to adverse fetal outcomes. Furthermore, maintenance of maternal glucose homeostasis and overexpression of placental growth factor (PGF) in the obesity-resistant group likely protected the placenta and fetuses from morphological and functional damage.