title: Hypercalcemia in a calcitriol-treated hypoparathyroid woman during lactation.
abstract: 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.
authors.affiliation: Department of Internal Medicine, Gundersen Clinic, Ltd., La Crosse, Wisconsin.
authors.forename: R H
authors.initials: RH
authors.lastname: Caplan
authors.forename: E A
authors.initials: EA
authors.lastname: Beguin
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002117:Calcitriol / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D002118:Calcium / Q000097:blood*; D004097:Dihydrotachysterol / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007011:Hypoparathyroidism / Q000097:blood / Q000188:drug therapy*; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy; D007774:Lactation / Q000097:blood; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000188:drug therapy
chemical_list: D002117:Calcitriol; D004097:Dihydrotachysterol; D002118:Calcium