The Gastrointestinal System
At birth, gastric pH is alkalotic; by the second day of life,
pH is in the normal physiologic range for older patients. The ability to coordinate
swallowing with respiration does not fully mature until the infant is 4 to 5 months
of age, thus resulting in a high incidence of gastroesophageal reflux in newborns
[39]
—a very common problem in preterm infants.
In general, if a developmental problem occurs within the gastrointestinal system,
symptoms will occur within 24 to 36 hours of birth. Upper intestinal abnormalities
are manifested as vomiting and regurgitation, whereas lower intestinal abnormalities
produce abdominal distention and failure to pass meconium.
