Transient neonatal hypocalcaemia caused by maternal hyperparathyroidism

Hypocalcaemia in neonates can range from asymptomatic to a potentially life-threatening condition. We present a case of a 36 weeks gestational age boy, admitted to our neonatal intensive care unit for jitteriness, mild hypotonia and breastfeeding difficulties. By the ninth day of life, he presented with late-onset hypocalcaemia, hypomagnesaemia, low 25-OH-vitamin D and inappropriately normal parathyroid hormone. Further investigation revealed maternal hypercalcaemia with high parathyroid hormone. Maternal asymptomatic hyperparathyroidism was diagnosed and admitted as the cause of neonatal hypocalcaemia. There was a clinical improvement and calcium levels stabilisation after treatment with calcium gluconate and vitamin D₃ This case highlights the importance of careful evaluation of neonatal late-onset hypocalcaemia in uncovering asymptomatic maternal hyperparathyroidism.