Risk factors of mild rectal bleeding in very low birth weight infants: a case control study

BACKGROUND Mild rectal bleeding (MRB) is a particular clinical entity different from necrotizing enterocolitis, which significantly influences neonatal care in preterm infants. We aimed to determine the risk factors and to evaluate prospectively the clinical course of MRB. METHODS We consecutively included in a case-control study all infants with birth weight ≤ 1500 g or gestational age ≤ 32 weeks admitted to our unit, and presenting MRB, defined as either isolated or associated with mild clinical or radiological signs. We matched each Case with two Controls. Clinical data before, after and at time of MRB were collected, together with stool cultures at time of MRB (or at similar postnatal age in Controls). Multiple logistic regression analysis was performed to determine independent risk factors for the development of MRB. RESULTS During 4 years, among 823 very low birth weight (VLBW) infants admitted to our unit, 72 (8.8%) had MRB. The median duration of rectal bleeding was 1.1 [1-2] days and the fasting period lasted 2.9 [2-10] days. A relapse occurred in 24% of cases. In multivariate analysis, only hypertension during pregnancy (p = 0.019), growth restriction at onset of bleeding (p = 0.026), and exposure to ibuprofen (p = 0.003) were independent risk factors for MRB. In Cases there were more infants with Clostridium Difficile in stools than in Controls (p = 0.017). CONCLUSION Hypertension during pregnancy, even without intrauterine growth restriction, appeared to carry the same risk for MRB as exposure to ibuprofen and extrauterine growth restriction.