[Factors associated with cross-nursing in two cities in Southeast Brazil].

The objective was to estimate the prevalence of cross-nursing in two Brazilian cities and analyze factors associated with the practice. This was a cross-sectional study nested in a cohort of pregnant women recruited at public health services that offered prenatal care in two medium-sized cities in the State of Rio de Janeiro: one in Greater Metropolitan Rio and the other in the Mountainous Region, conducted from 2008 to 2010. The current study included women interviewed when their infants were six months old. Adjusted prevalence ratios were obtained with a Poisson regression model, and exposure variables that reached p ≤ 0.05 comprised the final model. Cross-nursing was practiced by 43.4% of the mothers in Greater Metropolitan Rio de Janeiro and 34.5% in Mountainous Region. Low socioeconomic status was associated with cross-nursing in both cities. In addition, in Mountainous Region the outcome was directly associated with adolescent motherhood, maternal schooling less than or equal to complete primary, and fewer than six prenatal visits. In Greater Metropolitan Rio de Janeiro, in addition to socioeconomic status, only multiparity was associated (inversely) with cross-nursing. Cross-nursing, although contraindicated by the Brazilian Ministry of Health, showed high prevalence among the mothers in the sample and was more frequent among the more vulnerable population groups.