Hypercalcemia in a calcitriol-treated hypoparathyroid woman during lactation

Obstet Gynecol. 1990 Sep;76(3 Pt 2):485-9.


We treated a hypoparathyroid woman with calcitriol during pregnancy and did not reduce the dosage after delivery. Despite lactation, the serum calcium level increased to 15.4 mg/dL 11 days postpartum. We treated two other hypoparathyroid women during four pregnancies with either calcitriol or dihydrotachysterol. In all five pregnancies, requirements for the vitamin D preparations increased beginning at the 20-28th week of gestation. Hypercalcemia did not occur in the two women who did not breast-feed and in whom we reduced the dose of calcitriol or dihydrotachysterol after delivery. We conclude the following: 1) Calcitriol is effective for treating hypoparathyroidism during pregnancy; 2) the dose usually needs to be increased during the latter half of gestation; 3) the calcitriol dose should be reduced during lactation; and 4) both mother and infant should be monitored to detect hypercalcemia during breast-feeding. We speculate that low serum estrogen levels associated with breast-feeding promote bone resorption and diminish calcitriol needs in lactating hypoparathyroid women.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Calcitriol / administration & dosage
  • Calcitriol / adverse effects*
  • Calcitriol / therapeutic use
  • Calcium / blood*
  • Dihydrotachysterol / administration & dosage
  • Dihydrotachysterol / adverse effects*
  • Dihydrotachysterol / therapeutic use
  • Female
  • Humans
  • Hypoparathyroidism / blood
  • Hypoparathyroidism / drug therapy*
  • Hypothyroidism / blood
  • Hypothyroidism / drug therapy
  • Lactation* / blood
  • Pregnancy
  • Pregnancy Complications* / blood
  • Pregnancy Complications* / drug therapy


  • Calcitriol
  • Dihydrotachysterol
  • Calcium