This study aimed to determine the protective role of boric acid in a pregnant rat model of high fructose corn syrup consumption. Consumption of high fructose corn syrup has been associated with adverse health outcomes in humans and animals. Twenty-eight healthy female Wistar albino rats (250-300 g weight and 16-24 weeks old) were randomly distributed into four equal groups (n = 7): Control, Boric acid (BA), High Fructose Corn Syrup (HFCS), HFCS + BA. Boric acid (20 mg/kg) was administered to pregnant rats via oral gavage every day during pregnancy. The prepared 30% HFCS (F30) solution (24% fructose, 28% dextrose) was added to the drinking water throughout pregnancy. At the end of pregnancy (day 19), blood, placenta, uterus, and fetuses were collected from rats. The results indicated that HFCS increases oxidative stress by increasing the level of MDA and decreasing GSH, SOD, and CAT activity in the blood of maternal. However, BA administration significantly decreased MDA levels and increased GSH levels, SOD, and CAT activity (p <
0.05). In addition, HFCS consumption significantly increased plasma TNF-α, IL-6, and leptin levels compared to control, BA, and HFCS + BA groups (p <
0.05). However, BA administration significantly decreased plasma TNF-α, IL-6, and leptin levels (p <
0.05). Furthermore, BA (20 mg/kg) significantly decreased HFCS-induced histopathological and immunohistochemical alterations in the placenta, uterus, and fetal tissue. In conclusion, BA may prevent HFCS toxicity in maternal and fetal tissues, as it regulates oxidative imbalance in pregnant rat and alleviates histopathological and immunohistochemical changes. The findings indicate a need for further studies to assess the potential of boron in preventing or mitigating the effects of HFCS during pregnancy.