Purpose: To verify the prevalence of developmental defects of enamel (DDE) in deciduous teeth and analyse the association with adverse events that occurred during pregnancy and early childhood. Materials and Methods: In a cross-sectional study, 152 children with an average age of 3.57 ± 1.25 years were examined according to the criteria established by the DDE index. A previously validated questionnaire was given to mothers in order to obtain information regarding: calcium and vitamin D deficiency (measured in mothers); gestational diabetes; gestational undernutrition; weight at birth; neonatal hypoxia; and presence of asthma in early childhood. The clinical exam was conducted by a single examiner calibrated for visual exams (Kappa = 0.84), outdoors on patios of schools with children and examiner knee to knee. Pearson's chi-squared test and Fisher's Exact Test (p 0.05) were used to determine statistically significant associations between the variables in study. The data were then analysed using a binary logistic regression regression. Results: 26.3% of children exhibited DDE. It was possible to verify a statistically significant association between DDE and vitamin D deficiency (p 0.01), calcium deficiency (p = 0.01), neonatal hypoxia (p = 0.026), and gestational diabetes (p = 0.04). The regression model allowed the conclusion that children who had neonatal hypoxia during childbirth, gestational diabetes or vitamin D deficiency during their gestation were 3.54, 12.47 and 6.40 more likely to exhibit signs of DDE, respectively. Conclusion: The prevalence of DDE was considered high and was associated with vitamin D and calcium deficiency during pregnancy, gestational diabetes, and neonatal hypoxia. Keywords: child, child health, dental enamel hypoplasia, pregnancy