Human milk expression in the first year postpartum among persons with low incomes

Expressing milk (i.e., human milk) is common in the USA, but practices are unknown among families in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). This study of a WIC population explores the practice of and reasons for expressing milk in the first year postpartum.

We analysed data from a longitudinal study to examine milk expression at 1, 3, 5, 7, 9, 11, and 13 months postpartum among breastfeeding persons enrolled in WIC with term singletons. We cross-sectionally analysed the weighted prevalence of milk expression at each survey month and report reasons for milk expression in the first 7 months.

Among the study participants who reported feeding human milk at Month 1, 70.4% expressed milk in the first 13 months postpartum. The prevalence of milk expression was 56.8% at Month 1 and decreased to 13.9% at Month 13 among those feeding any human milk that month. Reasons for expressing milk changed over time; in the first month, increasing milk supply, relieving engorgement, and having an emergency supply of milk were common. In later months, having a supply of milk available so that someone else could feed their infant was common.

Clinicians, health educators, WIC staff, and others working with WIC families can promote optimal expressed milk feeding and storage practices. Extra attention and support may be especially important in the first months postpartum when milk expression is common. Support for persons who are expressing milk can be tailored for reasons of milk expression.