Nutritional Vitamin B12 Deficiency in a Breastfed Infant Following Maternal Gastric Bypass

Breasfed infants of women who have had gastric or intestinal bypass procedures may develop nutritional deficiencies. We describe a 10-month-old exclusively breastfed white male infant who presented with vomiting, failure to thrive, and megaloblastic anemia. He was found to have vitamin B₁₂ deficiency. His mother had undergone a gastric bypass procedure for morbid obesity 2 years Prior to her pregnancy with this child. She had subclinical vitamin B₁₂ deficiency, with an abnormal Schilling test that corrected with the addition of intrinsic factor. Therefore, we believe that the mother's gastric bypass had caused a decrease in available intrinsic factor, resulting in subclinical vitamin B₁₂ deficiency and decreased breast milk B₁₂. Although she was asymptomatic, her breastfed infant developed symptomatic B₁₂ deficiency. This is the first reported case of a maternal gastric bypass resulting in vitamin B₁₂ deficiency in an infant. These mothers should receive vitamin supplements, including vitamin B₁₂ during and after pregnancy, and my require parenterally administered vitamin B₁₂.