[Maternal occupation and the duration of exclusive breastfeeding: results of a birth cohort in São Luís, in the State of Maranhão, Brazil].

In investigations determining the duration of exclusive breastfeeding (EBF), the variable paid maternal work is mostly dichotomized into no and yes. This study analyzes possible associations between the characteristics of maternal occupation and shorter EBF duration. A cohort study was conducted in a systematic sample of births in the city of São Luís (State of Maranhão, Brazil), in 2010. The variables type of maternal occupation, numbers of days worked/week and hours worked/day, if they work while standing for most of the time, and if they lift heavy objects at work were collected with 5,166 mothers of live births. The final sample of this study had 3,268 observations. Survival analysis was used to evaluate associations between variables and EBF outcomes up to 4 months (EBF4) and EBF up to 6 months (EBF6). Not having paid work was the reference category. Adjusted Cox regressions showed that mothers with semi-specialized manual work (95% confidence interval, 95%CI: 1.02-1.58 for EBF4 and 95%CI: 1.11-1.56 for EBF6) and mothers who worked 8 or more hours daily (95%CI: 1.01-1.36 for AME4 and 95%CI: 1.11-1.41 for ESA6) more frequently discontinued EBF. Mothers with in-office occupations (95%CI: 1.07-1.46), who worked 4-5 days (95%CI: 1.01-1.36) or 6-7 days/week (95%CI: 1.09-1.40) and for 5-7 hours (95%CI: 1.03-1.43) also practiced less EBF6. Working (95%CI: 1.08-1.40) or not (95%CI: 1.03-1.34) while standing for most of the workday and lifting (95%CI: 1.07-1.56) or not (95%CI: 1.06-1.33) heavy objects at work decreased the duration of EBF6. Types of occupation and working time interfered more frequently in the duration of EBF6.