Critical weight loss and malnutrition in breast-fed infants.

In four infants of primiparous mothers, critical dehydration, hypothermia, and azotemia developed while they were being breast-fed exclusively. Three had significant hypernatremia, one had a perforated duodenal ulcer, and one had transient renal failure. Although the causes of the inadequate nutrition are unclear, these cases emphasize the necessity of close follow-up for breast-fed babies, especially those of primiparous mothers and those in whom there has been excessive weight loss while in the hospital.