Pregnancy with primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) in pregnancy is rare. The physiological changes that occur in pregnancy often tend to mask the symptoms of PHPT, thereby making diagnosis challenging. If left undiagnosed, PHPT can lead to significant feto-maternal morbidity, which, primarily depends on maternal serum calcium levels. Maternal serum calcium > 11.4 mg/dl increases the risk of incident maternal and fetal complications. The diagnosis of PHPT in pregnancy is based on the documentation of parathyroid hormone-dependent hypercalcemia. Ultrasonography can be safely used to localize the culprit parathyroid lesions; other imaging modalities entailing the risk of exposure to ionizing radiation should preferably be avoided. Treatment involves parathyroid surgery (preferably performed in the second trimester) and/or medical management (hydration, use of calcium-lowering drugs like calcitonin and/or cinacalcet) and should be tailored to the term of pregnancy, severity of hypercalcemia, potential maternal-foetal risks involved, available surgical expertise and patient's choices.