RESUMO
BACKGROUND: Being an adolescent mother and cohabiting with the maternal grandmother have been shown to be risk factors for a shorter breastfeeding duration. The objective of this study was to assess whether the positive effects of a pro-breastfeeding intervention aimed at adolescent mothers and maternal grandmothers on the prevalence of breastfeeding observed in the first year of life were maintained at 2 years of age. METHODS: This study is the continuation of a randomized clinical trial initiated in 2006 involving 323 adolescent mothers, their newborns and maternal grandmothers when cohabiting. The intervention consisted of six breastfeeding counseling sessions, the first one held at the maternity ward and the others at the participants' homes at 7, 15, 30, 60, and 120 days postpartum. The present study reports data collected when the children were 4 to 7 years old, concerning the maintenance of breastfeeding at 2 years. Data were analyzed using multivariable Poisson regression model with robust variance, with breastfeeding at 2 years of age as the outcome. RESULTS: Maintenance of breastfeeding for 2 years or more was present in 32.2% of the sample. When the intervention and control groups were compared, the prevalence of breastfeeding at 2 years was similar (29.9 vs. 34.3%, respectively; p = 0.605). Multivariable analysis failed to reveal an association between exposure to the intervention and maintenance of breastfeeding at 2 years in the different models tested. CONCLUSIONS: The positive impact of the intervention on the prevalence of breastfeeding observed in the first year of life was not maintained at 2 years of age. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov on May 28, 2009 under protocol no. NCT00910377.