This study is the continuation of a randomized clinical trial initiated in 2006 involving 323 adolescent mothers, their newborns and also their mothers (child’s maternal grandmothers) whenever cohabiting with the former. Sample selection procedures and intervention details are described elsewhere [15]. Briefly, adolescent mothers were selected at the inpatient obstetric ward of Hospital de Clínicas de Porto Alegre (HCPA) observing the following inclusion criteria: being 19 years old or younger, residing in the city of Porto Alegre, and breastfeeding their babies. Mothers of newborns weighing less than 2,500 g, of twins, or of newborns with congenital defects that could interfere with breastfeeding were excluded, as were mothers living with their mothers-in-law (paternal grandmothers).