Objective of the study: Developmental defects of enamel may lead to esthetic tribulations. Malformed dental enamel is usually susceptible to caries and sensitivity of teeth. The objective of the present study was to evaluate the distribution of developmental defects affecting the enamel surfaces in the teeth of newborn babies of the mothers, caused by the use of lithium for a long time during pregnancy. Study design/methods:The female rabbits were kept on this drug during pregnancy and their offsprings were used for the study. They were sacrificed to obtain their jaws. Teeth were extracted for assessment of the congenital defects developed during intrauterine life. Surface structure was studied by scanning electron microscopy and energy-dispersive X-ray microanalysis (SEM-EDX). Results:The results showed that the drug had caused erosions of the incisors and the molars, as compared to the premolars. Conclusion:According to the results, incisors and the molars appeared esthetically and functionally compromised teeth. The drug should, therefore, be used by doctor's prescription only, especially during pregnancy, avoiding the teratogenic effect on the dentition of the newborns.