Abstract
Primary hyperparathyroidism (PHPT) is rare in pregnancy and poses diagnostic challenges due to overlapping symptoms. This case series highlights diagnostic and management challenges in pregnant patients. Case 1: A 42-year-old woman at 33 weeks' gestation exhibited severe nausea and fatigue. Laboratory testing revealed elevated calcium 13.2 mg/dL (3.29 mmol/L) (reference range, 8.4-10.3 mg/dL [2.2-2.6 mmol/L]) and parathyroid hormone (PTH) 215 pg/mL (23.89 nmol/L) (reference range, 11-68 pg/mL [SI: 1.6-7.2 pmol/L]). Neck ultrasound identified bilateral parathyroid adenomas and abdominal ultrasound showed polyhydramnios. Parathyroidectomy resulted in calcium drop to 9.5 mg/dL (2.27 mmol/L) and PTH to 12 pg/mL (1.33 pmol/L). She delivered a healthy infant. Case 2: A 39-year-old woman at 39 weeks' underwent a cesarean delivery due to transverse fetal lie. She had high prepartum calcium of 14.2 mg/dL (3.55 mmol/L) and PTH 319 pg/mL (33.81 pmol/L). Post pregnancy, bilateral neck exploration and left inferior parathyroid excision decreased calcium to 8.9 mg/dL (2.22 mmol/L) and PTH to 16.5 pg/mL (1.75 pmol/L). These cases highlight that symptom severity-not just calcium level-should guide parathyroidectomy. Third-trimester surgery can be safely performed when symptomatic; asymptomatic patients may be managed expectantly. Early recognition and individualized management optimize maternal and fetal outcomes.