Primary hyperparathyroidism in pregnancy: a diagnostic and therapeutic challenge

The risk of severe complications arising from primary hyperparathyroidism (pHPT) is increased during pregnancy. Gestational pHPT often goes undiagnosed, and by the time it is diagnosed, a majority of women have endured one or more failed pregnancies. During pregnancy, active transport of calcium ions from the mother to the fetus leads to suppression of the fetal parathyroids. When the prenatal pool of calcium is depleted, the newborn may develop neonatal hypocalcemic tetany. The mother, in turn, may suffer from worsening hypercalcemia and a hypercalcemic crisis after delivery. Awareness and confirmation of the diagnosis may be crucial for the outcome. The only definitive treatment of pHPT is parathyroidectomy, which should be recommended in most cases. Our two cases illustrate both the importance of and the difficulty in detecting pHPT during pregnancy, as well as some of the serious complications that may occur during pregnancy and after delivery.