BACKGROUND Nausea and vomiting are common in the early period of pregnancy and rarely seen as an overture to pancreatitis. METHODS Here, we describe a 31-year-old pregnant woman who presented with progressive nausea and vomiting followed by severe epigastric pain. Biochemical data and sonographic features confirmed the occurrence of acute pancreatitis. Accompanying electrolyte abnormalities included hypercalcemia and hypokalemia. Her condition stabilized following medical treatment, but hypercalcemia persisted despite intravenous fluids and furosemide administration. METHODS A diagnosis of primary hyperparathyroidism was made based on the elevated parathyroid hormone level and urinary calcium-to-creatinine clearance ratio. METHODS Localization study with neck ultrasonography indicated left inferior parathyroid adenoma. She underwent parathyroidectomy successfully and made an uneventful recovery. RESULTS At 37 weeks of gestation, she had a serum calcium level of 8.8 mg/dL and normal parathyroid hormone of 28.55 pg/mL. A healthy baby weighing 3180 g was delivered smoothly with no clinical nor biochemical evidence of hypocalcemia. CONCLUSIONS Although primary hyperparathyroidism during pregnancy is usually asymptomatic, patients may present with atypical manifestations such as hyperemesis and pancreatitis. Proper diagnosis and timely intervention are crucial to minimizing potential hazards to both mother and fetus.