Lucci, T.K. (2013). Infant development from the Evolutionary Developmental Psychology perspective: infants of postpartum depressed mothers. Dissertação de Mestrado, Instituto de Psicologia, Universidade de São Paulo, São Paulo. The mother-infant bond, created from the earliest dyadic interactions, affects the infant emotional development. The postpartum depression (PPD) is a depressive disorder that can impair the quality of these interactions. During the first year of life the infant is particularly susceptible to external stimuli and totally dependent on parental care. The goal of the research reported in the dissertation was to investigate the impact of PPD on psychomotor development in a sample of children living in an urban area of the city of Sao Paulo, Brazil. This study is part of a FAPESP Thematic Project which aimed to investigate the risk factors related to Postpartum Depression (PPD) and its influence on children's development over the first three years of life. Mothers' mental state was assessed by the Edinburgh Postpartum Depression Scale (EPDS) at four and eight months after delivery and neurodevelopmental milestones were evaluated at four (N = 144), eight (N = 127) and twelve months (N = 94) through items based on Gesell and Amatruda, M-Chat, Denver and IRDI. Information was also collected about pregnancy, birth and neonatal evaluation from University Hospital reports. The sex ratio was biased at birth in favor of girls, consistent with Trivers and Willard Theory that harsh environmental conditions affects sex-ratio.Data were analyzed through logistic regression, considering the influence of postpartum depression, sex, age and day-care support. The results showed that child development was negatively affected by maternal postpartum depression at eight and twelve months, but not at four months. The baby's sex was also significant. At eight month male babies had worse psychomotor performance when compared to female, in accordance with literature showing that boys of PPD mothers are at greater risk of poor development. Unlike expected, at 12 months children attending day-care service showed poorer performance when compared to children who stayed at home. The high prevalence of PPD in this population (26,7%) and the results of the developmental evaluation are worrying, pointing to the need for mental health public policies and early intervention. Even in adverse conditions high impact solutions can be created, as Kangaroo care method. Furthermore, the results of this research can contribute to a multidisciplinary effort, relevant to address issues related to depression.