Background Accumulating research suggests that exposure to intra-familial adversities are significant risk factors for adverse pregnancy outcomes. However, the relationship between social violence (peer violence, witnessing community violence and exposure to collective violence) and pregnancy outcomes has not been extensively investigated. Our study aims to examine the association between social Adverse Childhood Experiences (ACEs) and pregnancy outcomes and to explore the role of depression during pregnancy as a mediator of this association. Methods We performed a prospective follow-up study of pregnant women in five Primary Health care Centers (PHC) in the region of Monastir (Tunisia) from September 2015 to August 2016. Enrolled women were followed during the second trimester, third trimester of pregnancy and during the postnatal period. Exposure to violence was assessed retrospectively using the validated Arabic version of the World Health Organization (WHO) ACE questionnaire. The Self Reporting Questionnaire 20-Item (SRQ-20) was used as a screening tool for depression during pregnancy. Results We recruited and followed a total of 593 women during the study period. Witnessing community violence was the most frequently reported social ACE among pregnant women (237; 40%), followed by peer violence (233; 39.3%). After adjustment for high risk pregnancies, environmental tobacco smoke, and intra-familial ACEs, the risk of premature birth was significantly associated with exposure to collective violence (P < 0.001) and witnessing community violence (P < 0.05). The risk of low birth weight was significantly associated with witnessing community violence (P < 0.001). In the mediation analysis, depression mediated significant proportions of the relationship between the cumulative number of ACEs and pregnancy outcomes. Conclusions Social ACEs may have a long-term effect on maternal reproductive health, as manifested by offspring that were of reduced birth weight and shorter gestational age. A public health framework based on the collaboration between pediatric, psychiatric obstetrical health professionals, education professionals and policy makers could be applied to ensure primary prevention of childhood adversities and pay attention to expected mothers with history of exposure to such adversities.