A 32-year-old primigravida at 8 weeks gestation presented with severe hyperemesis gravidarum, marked weight loss and dehydration. Biochemistry revealed hypercalcemia (corrected calcium 2.82mmol/L) and elevated parathyroid hormone (10.7pmol/L), leading to a diagnosis of primary hyperparathyroidism. 24-hour urine calcium excluded familial hypocalciuric hypercalcemia. The patient received supportive care including intravenous fluids and fortnightly calcium levels. While her hyperemesis improved by 15 weeks, her corrected calcium remained elevated (2.79mmol/L), prompting consideration for parathyroidectomy in the second trimester. Neck ultrasound suggested a possible enlarged right inferior parathyroid gland. 4DCT was suspicious for one right mid posterior 7mm parathyroid. A right unilateral parathyroid exploration is planned for 23 weeks gestation.
PHPT is the leading cause of hypercalcaemia in pregnancy, yet its prevalence is low and presentation often subtle. (1) Untreated maternal hypercalcaemia confers substantial maternal and foetal risks including pre-eclampsia, prematurity, growth restriction, and post‑natal hypocalcaemia or tetany. Adverse outcomes correlate with the degree of maternal calcium elevation, with miscarriage rates rising when corrected calcium exceeds 2.85mmol/L. (2,3)
Management hinges on timely surgical intervention. Localisation imaging is limited to ultrasound due to concerns regarding radiation and contrast exposure. 4DCT with foetal shielding, and limiting radiation and contrast has been used successfully in our centre for localisation. Acute stabilisation comprises aggressive hydration, electrolyte correction and vitamin D optimisation. Loop diuretics, bisphosphonates and calcimimetics are generally avoided given limited safety data. Definitive cure is parathyroidectomy, optimally performed in the second trimester (12–24 weeks), when organogenesis is complete and the risk of preterm labour remains low. Postpartum, careful monitoring is essential as the loss of placental calcium transfer can lead to an exacerbation of maternal hypercalcemia. Genetic testing is advisable in specific clinical contexts. (1,4)
Early recognition and coordinated surgical management are critical to safeguarding both maternal and foetal outcomes in pregnancies complicated by PHPT.