Evaluation of in utero developmental toxicity of metformin hydrochloride in male albino rats

Metformin is an oral antidiabetic drug of the biguanide family that is used in the management of diabetes and some forms of female factor infertility.It readily crosses the placenta and thus its safety in pregnancy is a concern.This study assessed the inutero developmental toxicity of metformin in rats.Sixteen albino rats were grouped into four with each group consisting of three females and one male.The rats were allowed to mate till pregnancy.The female rats in group A received metformin throughout pregnancy, the female rats in group B received metformin in the first 13.5 days of pregnancy while the female rats in group C received metformin from day 13.5 of pregnancy till delivery.The rats received metformin by oral gavage at a dose of 300mg/kg/day.The females in the control group D did not receive the drug.The pregnant females and their litters, following delivery, were monitored till 14 days after birth.The result of the study showed that the administration of metformin during pregnancy did not result in any significant maternal or fetal developmental toxicity.Pregnant females treated with metformin showed poor weight gain and transient treatment-related side effects.There was no external fetal structural abnormalities such as abnormal tail, vertebral, cranial or facial abnormalities, severe developmental retardation or undescended testes in any of the litters.At therapeutic doses, metformin is safe in pregnant rats.