Title: Familial Hypocalciuric Hypercalcaemia in Pregnancy
Rodrigo, Natassia1, Park, Kris2
1Endocrinology Advanced Trainee, Nepean Hospital, Kingswood NSW,
2Endocrinologist, Nepean Hospital, Kingswood NSW, Australia
Introduction: Familial hypocalciuric hypercalcaemia (FHH), benign
outside of gestation, becomes potentially life threating for a neonate born to
an affected mother as it can cause neonatal hypocalcaemia, seizures and tetany1.
Thus, it is an important condition to recognise in pregnancy.
Case: A 26 year old, Gravida 3, Para2, lady presented for review at
11 weeks gestation, with asymptomatic hypercalcaemia of 2.91mmol/L (2.13-2.63)
and parathyroid hormone (PTH) level of 3.6 pmol/L (1.0-6.8). She had a
background history of FHH, confirmed by genetic testing and a family history of
8 affected members. During her first pregnancy her calcium levels ranged from
2.9 - 3.09 mmol/L with PTH between 1.1- 2.3pmol/L. She underwent emergency
caesarean section due to failure to progress at 41 weeks gestation. She
delivered a healthy boy who was normocalcaemic and unaffected on genetic
testing. In her second pregnancy, her calcium ranged from 2.92- 2.97 mmol/L,
with PTH 1.1-4pmol/L. She underwent elective caesarean at 39 weeks gestation
and delivered a healthy girl, whose calcium was 3.08mmol/L (1.75-2.99).
Subsequent genetic testing confirmed her inheritance of FHH. This pregnancy she will undergo monitoring of
her calcium levels. Upon delivery, the neonate will undergo calcium monitoring
and genetic testing.
Discussion: FHH is an autosomal dominant condition caused by
inactivating mutations of the calcium sensing receptor2. 50% of
foetuses will be affected and have asymptomatic hypercalcaemia. Unaffected
foetuses risk foetal parathyroid suppression from maternal hypercalcaemia, with
complications including seizures described1.
1. 1.Cooper, Mark. (2011). Disorders
of calcium metabolism and parathyroid disease.Best Pract Res Clin
Endocrinol Metab. 25(6):975-83.
2. Christensen, Signe et al. (2011). Familial
hypocalciuric hypercalcaemia: a review. Curr Opin
Endocrinol Diabetes Obes.