The study was stopped when 85% of the sample wascompleted due to the time elapsed and the estimated lack of change in results.

This study evaluates the utility of measuring gastric residuals in premature infants born between 26+0 and 33+6 weeks and to determine if its routine use is related with a delay in feedings advancement in this babies compared with no measurement.

The evaluation of gastric residuals as a measure of enteral tolerance in term and especially preterm newborns is a widely used practice in different centers worldwide. However, until now, it continues to be a controversial practice, since its real usefulness is not clear.

Our study proposes to evaluate and compare two groups of preterm newborns born between 26 + 0/7 and 33 + 6/7 weeks, randomized to measure or not measure gastric residuals and determine if this practice delays the full feeding achievement.

Inclusion Criteria:

• Preterm infants born between 26+0 to 33+6 weeks post-menstrual gestational age.
• Enteral feeds starting during the first week of life.
• Signed informed consent from parents or guardians.

Exclusion Criteria:

• Perinatal asphyxia
• Sepsis and hemodynamic instability
• Major congenital malformations
• Surgical requirement during the first week of life
• Hemodynamic instability and vasoactive drugs requirement
• Moderate or severe respiratory failure with Oxygenation Index > 8