Maternal depression, a non-psychotic depressive episode of mild to major severity, is one of the major contributors of pregnancy-related morbidity and mortality. Maternal depression (antepartum or post partum) has been linked to negative health-related behaviours and adverse outcomes, including psychological and developmental disturbances in infants, children, and adolescents. Despite its enormous burden, maternal depression in low-income and middle-income countries remains under-recognised and undertreated. In this Series paper, we systematically review studies that focus on the epidemiology of perinatal depression (ie, during antepartum and post-partum periods) among women residing in low-income and middle-income countries. Please contact the library to request a copy of this article - http://bit.ly/1Xyazai