Abstract
Hyperparathyroidism is a rare disease during pregnancy, which has increased risks, including miscarriage and fetal growth restriction. However, the diagnosis of hyperparathyroidism is frequently not recognised or delayed as symptoms are non-specific and calcium is not routinely measured. With a thorough medical history and clinical suspicion, early diagnosis and treatment can reduce the risk of some pregnancy complications. A 35-year-old woman presented at 13/40 with hyperemesis gravidarum. She had elevated serum calcium and a parathyroid lesion on ultrasound. She underwent a parathyroidectomy with rapid normalisation of her calcium. Histopathology confirmed a parafibromin-deficient parathyroid tumour, suggestive of hyperparathyroidism jaw tumour syndrome. At 30/40, she presented with pre-eclampsia (hypertension, hyper-reflexia, proteinuria and intrauterine growth restriction) and had a caesarean section at 30+1/40, delivering a male infant, 897 g (fifth percentile). She had a prior 12-month history of chronic constipation and nephrolithiasis but was not investigated further despite elevated calcium (2.82 mmol/L).