Clinical data of 3 pregnant women with primary hyperparathyroidism admitted in Jinan Maternal and Child Health Hospital from 2013 to 2021 were retrospectively reviewed. Hyperparathyroidism was diagnosed during pregnancy in all 3 cases. The clinical manifestations were non-specific, such as nausea, vomiting, anorexia, and fatigue. Patients also had gallbladder stones (1 case), gallbladder polyps (1 case), and renal parenchyma changes (2 cases). The hypercalcemia crisis occurred in all 3 cases, the blood Ca 2+ levels were 4.11 mmol/L, 2.92-3.82 mmol/L and 3.49-4.10 mmol/L, respectively; and preeclampsia developed in 2 cases. Sudden death occurred in case 1 who did not receive effective treatment during pregnancy; blood calcium was well controlled during pregnancy in case 2, and her neonate had hypocalcemia with good prognosis; case 3 underwent surgical treatment in early pregnancy, and then had missed abortion. Pathological examination revealed parathyroid tumors in all 3 cases.