Abstract
Lactating mothers of preterm infants who are pump-dependent are at high risk for difficulty maintaining an adequate milk supply. This article reports the naturally occurring volume of milk removed from the breast by mechanical expression over time for 81 mothers of nonnursing preterm infants from 4 tertiary care centers in the Midwest. Baseline variables (infant gestation in weeks; intended length in weeks to breastfeed; number of hours postdelivery to first breast stimulation; infant weight in grams; timing of decision to provide mother's milk; income; maternal education, kangaroo care during week 1; previous breastfeeding experience; white, non-Hispanic) and day 4 variables (milk volume, frequency of pumping) were explored for predicting milk adequacy at week 6. Using the significant predictive variables of milk levels at day 4 and income, the logistic regression accurately classified 85% of the 40 mothers with inadequate milk production (<500 mL/d) and 85.5% of the 41 mothers with adequate milk production (>=500 mL/d). While controlling for income, the 27 mothers with lowest milk production at 4 days were 9.5 times more likely to have an inadequate milk supply at 6 weeks than the 54 mothers with higher milk production. While controlling for day 4 milk production, lower annual income mothers (<$50,000) were 5 times more at risk of inadequate milk production than those with high income (>=$50,000) at week 6. This study emphasizes the importance of the amount of milk volume expressed in the early postpartum period during lactogenesis. In addition, neonatal nurses need to be cognizant that income levels may make a difference in milk production.