The objective of this study is determining if enteral administration of Lactated Ringer's solution (LR) in preterm infants with feeding intolerance enables for faster advancement of milk feeding than fasting.

Feeding intolerance is a common problem in premature infants in the Neonatal Intensive Care Unit. Definition is clinical and based on abdominal distension, abdominal tenderness, emesis, change in gastric residuals, presence of blood in stool, and apnea with bradycardia.

Feeding intolerance is associated with serious complications: necrotizing enterocolitis, longer hospitalization and prolonged intravenous nutrition complications (e.g. sepsis, liver damage). Therefore, the investigators aim to achieve adequate enteral nutrition as soon as possible.

Because LR is a an amniotic fluid-like solution, it may improve gastro-intestinal function and avoid fasting, as well as its multiple problems (e.g. intestinal atrophy and decreased intestinal motility). LR was chosen as the test solution because of experience documenting its safe use in comparable groups: in newborn resuscitation parenterally, in amnioinfusion, and in bowel irrigation. Moreover, LR is similar in electrolytes composition to the experimental solution used in previous studies by Barney et al in neonates.

Inclusion Criteria:

• Birth gestational age (GA) between 25 and 32 weeks

• Corrected gestational age less than 34 weeks

• Enteral feeding tolerated at a minimum of 10 ml/kg/day for a minimum of 48 hours

• Severe feeding intolerance, defined as a minimum of one or more of the following signs leading to withholding of milk feedings on two evaluations over 12 to 24 hours:

  1. Significant increased abdominal girth, as evaluated by the treatment team, with abdominal tenderness
  2. Visible enlarged bowel loops with abdominal tenderness
  3. Recurrent emesis leading to withhold feeds
  4. Gastric residuals in excess of one feeding, recurrent or with growing abdominal girth
  5. Visible blood in stools without anal etiology

• Documented informed consent for participation in the study

Exclusion Criteria:

• Infants who already reached full enteral feeds for 72 hours, in fact a minimum of 130 ml/kg/day enteral feeds without parenteral supplementation.
• Small for gestational age (SGA) (weight at or less than the 3rd percentile on the Fenton growth chart)
• NEC (Bell's stage II or higher, radiologic evidence of NEC, pneumatosis intestinalis or free intraperitoneal air)or history of NEC
• Gastric or intestinal occlusion (no transit, absent bowel sounds, incessant vomiting, bile stained vomiting or air fluid levels)
• Major congenital malformation
• Septic infants requiring therapeutic antibiotics or antimycotics (infants only on prophylactic antibiotics or antimycotics should not be excluded).
• Patients judged as being too ill to enroll in this study, as defined by a requirement for mechanical ventilation with >50% FIO2
• Patent Ductus Arteriosus requiring ibuprofen, indomethacin or ligature, until one week after the end of treatment
• Intraventricular Haemorrhage grade 3 or 4
• Hypernatremia ≥ 150 mmol/L