Mother's own milk (MOM) is protective against gut microbiota alterations associated with necrotizing enterocolitis (NEC) and feeding intolerance among preterm infants. It is unclear whether this benefit is preserved with donor milk (DM) feeding. We aimed to compare microbiota development, growth, and feeding tolerance in very-low-birth-weight (VLBW) infants fed an exclusively human milk diet of primarily MOM or DM. One hundred and twenty-five VLBW infants born at Texas Children's Hospital were enrolled and grouped into cohorts based on percentage of MOM and DM in enteral feeds. Feeds were fortified with DM-derived fortifier per unit protocol. Weekly stool samples were collected for 6 wk for microbiota analysis [16S ribosomal RNA (rRNA) sequencing]. A research nurse obtained weekly anthropometrics. Clinical outcomes were compared via Wilcoxon's rank-sum test and Fisher's exact test, as well as multivariate analysis. The DM cohort (n = 43) received on average 14% mothers’ milk compared with 91% for the MOM cohort (n = 74). Diversity of gut microbiota across all time points (n = 546) combined was increased in MOM infants (P < 0.001). By 4 and 6 wk of life, microbiota in MOM infants contained increased abundance of Bifidobacterium (P = 0.02) and Bacteroides (P = 0.04), whereas DM-fed infants had increased abundance of Staphylococcus (P = 0.02). MOM-fed infants experienced a 60% reduction in feeding intolerance (P = 0.03 by multivariate analysis) compared with DM-fed infants. MOM-fed infants had greater weight gain than DM-fed infants. Compared with DM-fed infants, MOM-fed infants have increased gut microbial community diversity at the phylum and genus levels by 4 and 6 wk of life, as well as better feeding tolerance. MOM-fed infants had superior growth. The incidence of NEC and other gastrointestinal morbidity is low among VLBW infants fed an exclusively human milk diet including DM-derived fortifier. This trial was registered at clinicaltrials.gov as NCT02573779.

Randomised controlled trials are the gold standard to assess the effectiveness and safety of clinical interventions; however, many paediatric trials are discontinued early due to challenges in patient enrolment. Hence, most paediatric clinical trials suffer from lack of adequate power. Additionally, trials are expensive and might expose patients to unproven therapies. Alternatives to overcome these issues using virtual patient data-namely, digital twins, synthetic patient data, and in-silico trials-are now possible due to rapid advances in digital health-care tools and interventions. However, such digital innovations have been rarely used in paediatric trials. In this Viewpoint, we propose using virtual patient data to empower paediatric trials. The use of virtual patient data has the advantages of decreased exposure of children to potentially ineffective or risky interventions, shorter trial durations leading to more rapid ascertainment of safety and effectiveness of interventions, and faster drug approvals. Use of virtual patient data could lead to more personalised treatment options with low costs and could result in faster clinical implementation of interventions in children. However, ethical and regulatory concerns, including replacing humans with digital data, data privacy, and security should be addressed and the safety and sustainability of digital data innovation ensured before virtual patient data are adopted widely.