Quantifying the Association between Pump Use and Breastfeeding Duration.

OBJECTIVE: To quantify the extent to which pump use is associated with breastfeeding duration. STUDY DESIGN: We conducted a cross-sectional analysis of weighted data from the Centers for Disease Control and Prevention Pregnancy Risk Assessment Monitoring System from Maine, Michigan, New Mexico, and Utah between 2016 and 2021. Included respondents had a live-born infant at survey completion, initiated breastfeeding, and had nonmissing data for reported pump use and breastfeeding duration. Using Cox proportional hazard regression, we quantified the hazard of breastfeeding cessation and median duration (weeks) of breastfeeding by pump use. Pump use was suspected to be differentially impacted by race and ethnicity; an interaction was tested in our regression model. RESULTS: Our sample included 19 719 mothers (weighted n = 723 808) with mean age (SD) 29.5 years (5.6). Mothers with age <18 years, Medicaid enrollment, race, and ethnicity other than non-Hispanic White, lower income or education, and unmarried status demonstrated lower pump use (P < .001). Pump use was associated with 37% lower hazard of breastfeeding cessation (adjusted hazard ratio 0.63; 95% CI: 0.56-0.70) and 21 additional weeks of breastfeeding on average. The association varied by race and ethnicity (significant interaction observed between pump use and non-Hispanic Black mothers, P = .013); stratified analysis demonstrated the lowest hazard of breastfeeding cessation among non-Hispanic Black and Native American pump users (adjusted hazard ratio 0.47 [0.40-0.54] and 0.51 [0.37-0.70], respectively). CONCLUSIONS: Pump use was associated with longer breastfeeding duration; the greatest magnitudes of association were found among non-Hispanic Black and Native American participants, groups disproportionately affected by breastfeeding inequities. Future research examining the context around and causal impact of pump use on breastfeeding outcomes is needed.