Supplementary Material for: Cord obstruction and delayed cord clamping do not affect gut function in neonatal piglets

Introduction: Birth-related obstruction of umbilical blood flow may induce hypoxic insults that affect postnatal organ adaptation. Using newborn caesarean-delivered pigs, we hypothesized that cord obstruction during delivery negatively affects physiological transition and gut maturation. Further, we investigated if delayed cord clamping improves gut outcomes, including sensitivity to formula-induced necrotizing enterocolitis-like lesions (NEC). Methods: In Experiment 1, preterm (n=24) and near-term (n=29) piglets were subjected to umbilical cord obstruction (UCO, 5-7 min in utero), with corresponding pigs delivered without obstruction (CON, n=17-22). Experiment 2 assessed preterm pigs subjected to delayed cord clamping (DCC, n=30, 60 seconds) or immediate cord transection with umbilical cord milking (UCM, n=34). Postnatal vital parameters were recorded, together with a series of gut parameters after 3 days of formula feeding. Results: UCO induced respiratory-metabolic acidosis in near-term pigs at birth (pH 7.16 vs. 7.32, pCO2 12.5 vs. 9.2. kPa, lactate 5.2 vs. 2.5 mmol/L, p<0.05). In preterm pigs, UCO increased failure of resuscitation and mortality shortly after birth (88 vs. 47%, p<0.05). UCO did not affect gut permeability, transit time, macromolecule absorption, six digestive enzymes, or sensitivity to NEC-like lesions. In Experiment 2, DCC improved neonatal hemodynamics (pH 7.28 vs. 7.20, pCO2 8.9 vs. 9.9 at 2h, p<0.05), with no effects on gut parameters. Conclusion: UCO and DCC affect neonatal transition and hemodynamics, but not neonatal gut adaptation or sensitivity to NEC-like lesions. Our findings suggest that the immature newborn gut is highly resilient to transient birth-related changes in cord blood flow.