Factors Associated with Low Volumes of Mother's Own Milk at Neonatal Intensive Care Unit Discharge of Very Low Birth Weight Infants-a Cohort Study

Abstract

Background: Mother's own milk (MOM) provides health benefits for infants with very low birth weight (VLBW). This study aimed to describe the incidence and factors associated with low volumes of MOM (<50% of total diet volume) at discharge for VLBW infants. Methods: A prospective cohort study of infants with VLBW and gestational age of <30 weeks, who survived to discharge and had no contraindication to MOM. We conducted bivariate analyses to investigate associations with the volume of MOM at discharge, using chi-square, t, and Mann-Whitney tests. All p-value analyses were two-tailed. The variables significantly associated with "low volumes of MOM" entered the multivariable analysis. Univariate and multivariate relative risk (confidence interval [CI] 95%) estimates were obtained from Poisson regression with a robust estimate of variance and controlled by the length of hospital stay. Results: Of 414 infants included and followed until discharge, 32.9% (n = 136) received less than 50% of the total daily volume of MOM. This outcome was associated with gestational age <28 weeks, lower birth weight, multiple births, developing bronchopulmonary dysplasia, and longer lengths of stay. After Poisson regression, low volumes of MOM at discharge were associated only with being born multiples (RR 2.01; CI 95% 1.53-2.64, p < 0.001) and with longer length of stay (RR 1.07; CI 95% 1.01-1.14, p = 0.01). Conclusions: Most VLBW infants were discharged home receiving predominantly MOM. Each neonatal intensive care unit (NICU) should acknowledge which clinical characteristics of mothers and VLBW infants are associated with difficulties maintaining MOM volumes until discharge.

Keywords: breastfeeding; mother’s own milk; preterm infants; very low birth weight.