To assess trends and disparities in breastfeeding by maternal characteristics (race and ethnicity, age at delivery, obesity, parity, and level of education) and the relative importance among these for breastfeeding at 6 months.

This retrospective birth cohort study included 195 861 live singleton children born at 32-42 weeks of gestation from 2008 to 2015 within a single integrated healthcare system. All children had healthcare coverage during the first year of life. Maternal characteristics and breastfeeding status at 6 months of age were extracted from electronic medical records. Trends over time of any breastfeeding ≥6 months were evaluated for the 5 maternal characteristics. Robust Poisson regression models were used to estimate breastfeeding rate differences associated with each of the 5 characteristics. The relative importance among them associated with breastfeeding ≥6 months was assessed by comparing model quasi-likelihood information criteria.

Rates of breastfeeding ≥6 months significantly increased overall and among groups defined by the maternal characteristics. However, there was little improvement over time in closing disparities associated with maternal race and ethnicity, age at delivery, prepregnancy obesity status, and level of education. Education level contributed to the greatest disparity in breastfeeding ≥6 months. Maternal age was the second factor, followed by prepregnancy obesity and maternal race and ethnicity.

Breastfeeding outreach programs focusing on women with less than a college education, women <25 years old, and women from non-Hispanic black or Hispanic race and ethnicity may help to reduce disparities and improve breastfeeding persistence rates within integrated healthcare systems.