The Dose Effect of Maternal Milk on Bronchopulmonary Dysplasia in Very Low Birth Weight Infants

Abstract

Background Human breast milk has potential protective effects against bronchopulmonary dysplasia (BPD). However, limited multicenter research has been reported on the association between the dose of maternal milk and BPD in China. In this study, we aimed to evaluate the dose effects of maternal milk on BPD and other neonatal morbidities in very low birth weight (VLBW) infants. Methods We conducted a retrospective cohort study of preterm infants of gestational age ≤ 34 weeks and birth weight < 1500 g admitted to the multicenter clinical research database for breastfeeding quality improvement in Jiangsu province. Multivariate analysis was performed to compare the effect on neonatal outcomes of daily graded doses of maternal milk throughout the first 4 weeks of life versus a reference group receiving no maternal milk. Models were adjusted for potential confounding variables. Results Of 964 included infants, 279 (28.9%) received exclusive preterm formula, another 128 (13.3%) received 1–24 ml/kg, 139 (14.4%) received 25–49 ml/kg, and 418 (43.4%) received ≥ 50 ml/kg maternal milk for the first 4 weeks of life. Compared with infants receiving exclusive formula, those receiving the highest volume of maternal milk daily (≥ 50 ml/kg) had lower incidences of BPD (27.5% in ≥ 50 ml/kg maternal milk vs. 40.1% in formula), moderate and severe BPD (8.9% in ≥ 50 ml/kg maternal milk vs. 16.1% in formula), necrotizing enterocolitis (NEC; 3.8% in ≥ 50 ml/kg maternal milk vs. 10.8% in formula), late-onset sepsis (LOS; 9.3% in ≥ 50 ml/kg maternal milk vs. 19.7% in formula), and extrauterine growth retardation (EUGR; 38.5% in ≥ 50 ml/kg maternal milk vs. 57.6% in formula). Logistic regression indicated that those receiving ≥ 50 ml/kg/day maternal milk had lower odds of BPD (adjusted odds ratio [AOR] 0.453; 95% confidence interval [CI]: 0.309, 0.666), moderate and severe BPD (AOR 0.430; 95% CI: 0.249, 0.742), NEC (AOR 0.314; 95% CI: 0.162, 0. 607), LOS (AOR 0.420; 95% CI: 0.263, 0.673), and EUGR (AOR 0.685; 95% CI: 0.479, 0.979). Conclusions A daily threshold amount of ≥ 50 ml/kg maternal milk in the first 4 weeks of life was associated with lower incidence of BPD as well as NEC, LOS, and EUGR in VLBW infants. Trial registration: ClinicalTrials.gov Identifier: NCT03453502