BOWEL HABIT IN PRETERM NEWBORNS

Preterm or very low-birthweight infants often have delay in establishing propulsive activity in the gut. Objective. To assess the effect of gestational age, birth weight, way of delivery, feeding, sepsis on the timing of the first meconium passage as well as of intestinal canalization, meant as an emission of at least three spontaneous stool passages. Patients and methods. Medical records of 719 preterm infants (mean GA33±2.5, range 23–36, meanBW2023±626 range 330–4450) admitted to the Neonatal Intensive Care Unit between January 2000 and December 2005 were reviewed. Exclusion criteria: G.I. tract congenital malformation, NEC, Meconium ileus. Statistical analysis: All the variables analysed have been entered into a Cox regression model. Also survival curves have been calculated according Kaplan–Meier method. Results. First meconium passage turns out to depend exclusively on gestational age. The higher gestational age, the higher the likelihood for newborns to pass their meconium earlier (p < 0.001). Seventy percent of preterm newborns reaches intestinal canalization within two days after birth, but there are few subjects who reach canalization after the first week and more. Intestinal canalization depends on gestational age (p < 0.001) and on the first meconium passage (p < 0.001). The greater the volume of milk ingested, the greater the defecation rate. For each 50 ml/kg increase in the volume of milk ingested, the infants showed a further increase of one stool passed each day. In the absence of milk feeds, an intrinsic pattern of large bowel motor activity, present as early as 25 weeks’ gestation, ensures a defecation rate of one stool each day. The type of feeding (mother milk versus formula) does not seem to have an influence on first meconium passage, day of intestinal canalization, number of stool passed every day. Twenty-one preterms died for reasons other than gastrointestinal. In these babies intestinal canalization occurred later than the other preterm babies (p < 0.001). Conclusions. Delay in the passage of meconium after 24 h is often a sign of intestinal disorders; 94% of infants with Hirschprung disease and up to a quarter of infants with cystic fibrosis may not pass their first stool until more than 24 h after birth. Our data show that for preterm infants delay in passage of meconium beyond this time may occur in more than 30%, and thereafter bowel habit depends on gestational age and is regulated by the volume of milk ingested.