Primary hyperparathyroidism does not appear to impair fertility, but it is known to result in a high rate of fetal complications such as spontaneous abortions, stillbirths, and neonatal tetany. Maternal hyperparathyroidism causes maternal hypercalcemia, which in turn facilitates increased placental calcium transport. High fetal calcium concentrations suppress the fetal parathyroid so that after delivery the neonate is functionally hypoparathyroid. Deprived of its maternal source of calcium, the neonate becomes vulnerable to tetany in the immediate postpartum period.

Medical therapy for hyperparathyroidism during pregnancy is appropriate only for a short period. Surgical exploration of the neck is the recommended treatment for a pregnant patient with rising serum calcium concentration, worsening symptoms, or hyperparathyroid crisis unresponsive to medical therapy. Many authors believe that the high incidence of maternal and neonatal complications associated with hyperparathyroidism makes surgery the treatment of choice even if the disease is mild. Surgery should ideally be performed during the second trimester.