title: Hypercalcemia during pregnancy, puerperium, and lactation: review and a case report of hypercalcemic crisis after delivery due to excessive production of PTH-related protein (PTHrP) without malignancy (humoral hypercalcemia of pregnancy).
abstract: Hypercalcemia during pregnancy or after delivery is uncommon, and mostly associated with primary hyperparathyroidism (PHPT). If unrecognized, it may increase maternal and fetal morbidity. In a very few patients with PHPT, hypercalcemic crisis develops during pregnancy and particularly after delivery, since calcium transport from the mother to the fetus is abruptly disrupted. Hypercalcemia may also develop in pregnant women due to PTH-related protein (PTHrP)-producing malignant tumors (humoral hypercalcemia of malignancy). Since PTHrP is produced physiologically in fetal and maternal tissues, hypercalcemia may occasionally develop during pregnancy, puerperium, and lactation due to excessive production of PTHrP in the placenta and/or mammary glands. PTHrP may also be involved in milk-alkali syndrome that develops during pregnancy. Although non-malignant hypercalcemia is usually mild, we report a 28-years-old pregnant woman who developed hypercalcemic crisis after normal delivery of an infant. On the first postpartum day, the corrected serum calcium concentration increased to 19.4 mg/dl with a markedly increased serum level of PTHrP (28.4 pmol/L) (normal <1.1 pmol/L). After administration of saline and pamidronate, the serum levels of calcium and PTHrP rapidly normalized. Extensive examination revealed no malignant lesion, suggesting that the placenta may have been producing an excessive amount of PTHrP (humoral hypercalcemia of pregnancy). We review case reports of non-malignant hypercalcemic crisis associated with pregnancy indexed in PubMed in which serum levels of intact PTH and/or PTHrP were described, and stress that rapid control of hypercalcemia is mandatory to save the life of the mother and the infant.
authors.affiliation: Field of Pathophysiology and Treatment for Thyroid and Parathyroid Diseases, Division of Internal Medicine, Graduate School of Medicine, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Sato
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000150:complications / Q000175:diagnosis / Q000209:etiology*; D049950:Hyperparathyroidism, Primary / Q000150:complications* / Q000175:diagnosis; D044162:Parathyroid Hormone-Related Protein / Q000009:adverse effects / Q000097:blood / Q000378:metabolism*; D049590:Postpartum Period / Q000097:blood*; D011247:Pregnancy / Q000378:metabolism; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D044162:Parathyroid Hormone-Related Protein; D002118:Calcium