Most etiologies are self-limited and benign.
Maternal blood ingestion is the most common cause of suspected GI bleeding. Other common causes include gastritis, duodenitis, milk allergy, anorectal disorders, necrotizing enterocolitis, and midgut volvulus. This category includes esophagitis, gastritis, duodenitis, ulcers, and anorectal disorders. Other causes include infectious diarrhea, midgut volvulus, Meckel's diverticulum, AVM, and GI duplication. Rare causes include foreign body ingestions, variceal disease, and acquired thrombocytopenia.