Severe hypercalcemia in a lactating woman in association with moderate calcium carbonate supplementation: a case report.

Background: Lactation results in dramatic bone resorption and decreased urinary calcium excretion due to rapidly falling estrogen levels and probably increased levels of parathyroid hormone-related protein.

Case: A healthy, 36-year-old woman developed severe hypercalcemia several days after beginning breast-feeding her second child. During and after this pregnancy, she supplemented a high calcium diet with moderate amounts of calcium carbonate in an attempt to avoid an osteoporotic fracture that occurred while she was breast-feeding her first child.

Conclusion: Because the metabolic changes that occur during lactation predispose a woman to hypercalcemia, the daily recommended daily allowances for calcium should not be exceeded during breast-feeding.