Background: Phytotherapeutic treatment is used in the treatment of diabetes and its complications. The current study aims to evaluate the significant effect of supplementation of aqueous olive leaf extract (OLE) (Olea europaea) in the kidney of diabetic pregnant mice and their fetuses. Forty pregnant mice were divided into four groups contained 10 mice each after mating. The first group was the control (G1). The second group (GII) was intraperitoneally injected by a single dose of (240 mg/kg body weight) of streptozotocin (STZ). The third group (GIII) was administrated with a daily oral dose of extract of olive leaf extract (100 mg/kg) from days 1 to 18 of
gestation. The fourth group (GIV) was injected intraperitoneally by a single dose of (240 mg/kg body weight) of STZ and post-treatment with oral dose of extract of olive leaves from days 1 to day 18 of gestation. Results: Both mothers and their fetuses of STZ-induced diabetic group showed a decrease in weight compared to control and diabetic group supplemented OLE extract. According to the biochemical and histopathological observations, the STZ-induced diabetic group showed a significant (P < 0.05) increase in serum urea and creatinine levels parallel with detectable histopathological changes in kidney tissues of pregnant mice and their fetuses. Moreover, there was a significant decrease in serum urea and creatinine (P < 0.05) of diabetic mother group under treatment with OLE as compared to diabetic mice. Also, histological findings showed improved renal architecture as reflected by reduced glomerular and tubular necrosis in pregnant mice and their fetuses when compared with control group. Also, there was an increase in the anti-angiotensin II (Ang II) immunoreactivity in renal tubules, intraglomerular, and interstitial cells in the kidney tissue of STZ-induced diabetic group which was markedly improved by treatment with OLE.Conclusion: Oral administration of aqueous olive leaf extract to diabetic pregnant mice and their fetuses has ameliorative effect on weight gain as well as kidney functions and has the ability to minimize the damage in the kidney and placental tissue caused by hyperglycemia, and this effect may be attributed to its antioxidant activity. Conclusion: Oral administration of aqueous olive leaf extract to diabetic pregnant mice and their fetuses