Malignant hypercalcemia in pregnancy: effect of pamidronate on uterine contractions

Hypercalcemia in pregnancy can have devastating effects on both mother and fetus. Pamidronate, a bisphosphonate and inhibitor of bone resorption, has been used to treat hypercalcemia, but it is considered contraindicated in pregnancy.

A 40-year-old multigravida presented at 24 weeks of gestation with metastatic breast cancer. After unsuccessful chemotherapy, at 28 weeks of gestation she had deteriorating renal function, frequent contractions, and a calcium level of 17.6 mg/dL. When conventional treatment of hypercalcemia failed, pamidronate dramatically decreased both the calcium levels and the frequency of uterine contractions.

Pamidronate in pregnancy successfully reduced severe maternal hypercalcemia and uterine contractions. Although the reduction in calcium level did not prevent the development of preeclampsia or further deterioration in the mother's condition, it was not associated with any adverse effects on the neonate.