Gestational diabetes, occurs during the second or third trimester of pregnancy, with no prior history of diabetes; this entity can be resolved at the end of pregnancy. Magnesium is the fourth most abundant mineral in the body, It plays an essential role in the regulation of insulin metabolism, in the functions of adenosine triphosphate. In Mexico, the prevalence of hypomagnesemia is 36.3% for women. Findings suggesting that magnesium supplementation may be a beneficial indication in metabolic glucose disorders. The hypothesis of this study is: that Magnesium lactate administration is safe and reduces the incidence of gestational diabetes.