Relationship of birth weight to the pathogenesis of necrotizing enterocolitis in the neonatal piglet.

The relationship between birth weight and the development of necrotizing enterocolitis (NEC) was studied in the term-delivered neonatal piglet. Hypoxia (pO2 less than 30% for 1 h) coupled with hyperviscosity (hematocrit more than 75%), with and without splenectomy, resulted in a high frequency and severity of NEC. This effect was most pronounced in low birth weight (LBW) animals. A statistically significant inverse relationship was found between birth weight and the number and severity of lesions. Splenectomy increased the incidence and severity of lesions particularly in LBW animals. A predominance of lesions was found in the distal ileum with occasional occurrences elsewhere in the small bowel and in the proximal colon. The neonatal piglet is capable of producing the full spectrum of NEC under acceptable experimental conditions. LBW is a significant predisposing factor in the pathogenesis of NEC.