Validity of a 3-Hour Breast Milk Expression Protocol in Estimating Current Maternal Milk Production Capacity and Infant Breast Milk Intake in Exclusively Breastfeeding Dyads.

An efficient method for measuring maternal milk production is needed. Our objectives were to: (1) validate a milk production rate (MPR) protocol in exclusively breastfeeding mothers; (2) determine MPR change following 48 hours of increased breast emptying; (3) assess agreement between MPR and infant test-weighing; and (4) characterize MPR in early postpartum exclusively breastfeeding mothers.  = 23 mothers emptied both breasts hourly over 3 hours (h0, h1, h2, and h3). We estimated steady-state MPR as mean (h2 and h3). Subset A mothers ( = 5) also completed MPR measurements after 48 hours of increased breast emptying. Subset B mothers ( = 16) also test-weighed for 48 hours. We used paired -test to examine within-participant change in hourly milk yield and MPR; and we used Bland-Altman analysis to compare 24-hour milk production (g/24 hours) measured using test-weight versus MPR. Results are reported as mean ± standard deviation or (±95% limits of agreement). Mothers were 54 ± 14 days postpartum. Paired difference in h3-h2 hourly milk yield was not significantly different ( > 0.05, 3 ± 10 g/hour). In Subset A ( = 5), MPR declined from 50 ± 13 to 43 ± 16 g/hour ( = 0.003) following 48 hours of increased breast emptying. In Study B ( = 16), mean infant test-weighed intake (TW) was 717 ± 119 g/24 hours, and mean MPR was 1,085 ± 300 g/24 hours. Mean difference (MPR-test-weigh) and mean ratio (MPR/test-weigh) significantly increased as MPR increased ( < 0.05). For infants with adequate weight gain (>20 g/24 hours,  = 12), mean MPR = 48 ± 12 g/hour (range, 35-78 g/hour). MPR is a valid measure of current maternal milk production capacity, but is not accurate for evaluating infant intake in exclusively breastfeeding dyads.