Primary hyperparathyroidism during pregnancy.

Primary hyperparathyroidism during pregnancy is associated with significant risk of fetal loss and neonatal and maternal morbidity. Neonatal hypocalcemia probably results from transient hypoparathyroidism consequent to abnormal suppression by fetal hypercalcemia. Loss of the protective effect provided by the placental calcium transport mechanism produces significant maternal risk for development of acute hypercalcemia and possible crisis immediately postpartum. Management of maternal primary hyperparathyroidism diagnosed during pregnancy should be based on the patient's symptoms, severity of the disease, and gestational age of the fetus. Patients without symptoms and those with mild hypercalcemia may be managed effectively and safely for a short time with oral phosphate therapy, postponing operation until after delivery. More severe disease characterized by progressive symptoms and inadequately controlled hypercalcemia should be treated surgically after control of hypercalcemia has been achieved with diuretic and/or other medical therapy. Maternal operative morbidity is low and risk to the fetus is slight once organogenesis has been completed. Maternal parathyroidectomy should be performed preferably after the first trimester and should not be deferred unless delivery is imminent.