Nicotinamide participates in post transcriptional activities related to the maintenance of the original structure of the DNA. The chemotherapeutic agent cyclophosphamide induces severe chromosomal abnormalities in newborns. Thus, we investigated the possible protective effects of nicotine on the toxic and teratogenic model induced by cyclophosphamide. Pregnant mice were divided into experimental groups 1 and 2 (nicotinamide 100mg/ kg and 200mg/kg respectively); Experimental Group 3 (saline); Experimental group 4 (cyclophosphamide 50 mg/kg); Associated Treaty 5 and 6 (nicotinamide 100mg/kg and 200mg/kg associated with cyclophosphamide 50 mg/kg respectively). The results indicated that the exposure to nicotinamide in two doses, did not show any parameter of toxicity. We found that associated treatments 5 and 6 have been unable to minimize the adverse effects induced by cyclophosphamide on maternal toxicity and congenital malformations. However, the group associated with nicotinamide at a dose of 200mg/kg showed a protective effect on the increase in reabsorption rate, and nicotinamide in the two tested doses showed protective effects on decreased fetal and placental weight induced by cyclophosphamide. The results of this study showed that nicotinamide in a dose-dependent manner exerted protective effect and reduced the number of abortions and that the morbidity and mortality induced by cyclophosphamide was also reduced due to the nicotinamide.