Three case reports of maternal primary hyperparathyroidism in each trimester and a review of optimal management in pregnancy.

Primary hyperparathyroidism (PHPT) during pregnancy is associated with significant maternal and fetal risks. Prompt diagnosis and effective management during pregnancy can improve both maternal and fetal outcomes. However, there is no consensus with regard to conservative versus surgical management especially in the first and third trimester. We report three cases of PHPT associated with pregnancy that underwent parathyroidectomy each in a different trimester. Cases 1 and 2 were found to have hypercalcaemia and elevated parathyroid hormone levels in the second and first trimesters, respectively. Case 3 was known to have PHPT prenatally but previously declined parathyroidectomy. All three cases underwent parathyroidectomies during pregnancy without significant postoperative complications and all achieved favourable maternal and neonatal outcomes. Maternal hyperparathyroidism represents a preventable cause of maternal morbidity, with fetal morbidity and mortality. The benefits of parathyroidectomy with normalization of serum calcium in the mothers outweigh the risks of hypercalcaemia and suppression of the fetal parathyroid, especially where maternal vitamin D concentration is low.