ObjectiveTo identify non-psychotic affective disorders in pregnant women, to intervene by means of psychoprophylactic groups, and to evaluate possible alterations following intervention. Methods One-hundred and three pregnant women (71 adults and 32 adolescents) were seen at a community program in the Paraisópolis neighborhood in the city of Sao Paulo, southeastern Brazil. We used the following instruments: Self Reporting Questionnaire and Beck Depression Inventory. Ten weekly two-hour meetings were held, addressing the link between mother and fetus and subjects related to mother and child, and answering mother's doubts. We used the chi-squared test (χ 2 ) to compare mental health before and after the intervention, with a significance level of p<0.05. Results Affective disorders were found in 45 pregnant women (43.7%) before the intervention and in 23 (22.3%) after the intervention. The impact of the intervention on affective disorders was statistically significant (p=0.001). Twenty-one women (20.4%) showed depression before the intervention, and 13 (12.6%) after the intervention, a nonsignificant difference (p=0.133). Conclusions Multiprofessional care can prevent, detect, and treat affective disorders during pregnancy in both adults and adolescents. lated to family, marital relationship, society, culture, and the mother's personality.