Radiograph of infant with necrotizing enterocolitis.

A rather contentious issue at the recent Harvard Probiotics Symposium, which AMI was fortunate enough to attend, was the use of probiotics in treating necrotizing enterocolitis (NEC). NEC occurs in 7% of very low birth weight babies, and is caused by a bacterial infection in the gut. The mortality rate of children who suffer from NEC is around 25%. Many studies have shown that using human milk, rather than formula, to feed low birth weight infants, reduces risk of NEC, presumably by encouraging commensal bacterial growth, and this is now common practice in NICUs in the United States.

Several countries, including Australia and New Zealand, but not the United States, give a prophylactic probiotic to low birth weight infants immediately following birth to prevent NEC. Double blind randomized clinical trials demonstrate that using probiotics in these infants decreases both risk of NEC and mortality from NEC by half in each case.

Reviews of all the clinical data on using probiotics have shown that the studies have not been robust enough for US regulators to develop clinical guidelines regarding probiotics. These trials have occurred outside the US, so are under even more scrutiny. Adding more complexity to the issue is the fact that many of the studies used different probiotics, so how can they be compared? Now however, many of the countries providing probiotics to low birth weight infants require the probiotic administration as a course of treatment, thereby making controlled randomized trials unethical. Withholding probiotics would place these infants at a greater risk for NEC.

A recent commentary on the subject in the Journal Pediatrics points to the need for a robust randomized clinical trial to occur in the United States, to truly determine whether probiotics are useful in treating NEC. The AMI has not yet adopted a formal position on the subject, but we agree more work is needed.