Get your parcel fast via express flat rateVolume 3, December 2015, Pages 15–19 Management of hypoparathyroidism in pregnancy and lactation — A report of 10 casesa b c Received 17 December 2014, Revised 26 May 2015, Accepted 31 May 2015, Available online 30 June 2015•A review of 10 pregnancies with hypoparathyroidism presenting to a single centre•Causes of hypoparathyroidism includes idiopathic, congenital and post-thyroidectomy•Pre-existing hypoparathyroidism is associated with increased antenatal complications.•Monitor and maintain maternal corrected calcium levels in the low to mid-normal range•Dose reduction of calcitriol following delivery is needed IntroductionHypoparathyroidism in pregnancy is rare, but important, as it is associated with maternal morbidity and foetal loss. There are limited case reports and no established management guidelines. Optimal maintenance of calcium levels during pregnancy is required to minimise the risk of related complications. This study aims to identify causes and examine outcomes of hypoparathyroidism in pregnancy in a cohort of women delivering at a large referral centre.
Design and methodThe Monash Health maternity service database captures pregnancy and birthing outcomes in over 9000 women each year. We audited this database between 2000 and 2014 to examine the clinical course, treatment and outcomes of pregnant women with hypoparathyroidism.ResultsWe identified 10 pregnancies from 6 women with pre-existing hypoparathyroidism secondary to idiopathic hypoparathyroidism (n = 3), autosomal dominant branchial arch disorder with hypoparathyroidism (n = 3) and autosomal dominant hypocalcaemia (n = 1), surgery for thyroid cancer (n = 2) and Graves' disease (n = 1). Maternal calcium levels were monitored through pregnancy and management adjusted to maintain normocalcaemia. One woman was delivered by caesarean section at 34 weeks' gestation because of intrauterine growth restriction, and oligohydramnios complicated two other pregnancies. The postpartum period was complicated by severe hypercalcaemia in one woman and by symptomatic, labile serum calcium levels during lactation in another woman, requiring close monitoring over a 6 month period.
ConclusionAlthough rare, hypoparathyroidism in pregnancy poses a management challenge for clinicians, and co-ordinated care is required by obstetricians and endocrinologists to ensure optimal outcomes for both mother and baby. Continued monitoring of maternal calcium levels during lactation and weaning is essential to avoid the potential complications of either hypercalcaemia or hypocalcaemia.1. IntroductionHypoparathyroidism is rarely encountered during pregnancy but is important, however, as it is associated with maternal morbidity and foetal loss. Physiological adaptations to maternal calcium metabolism occur during pregnancy and lactation to facilitate mineralisation of the foetal skeleton and ensure adequate calcium in breast milk, whilst maintaining normal ionised and albumin-corrected serum calcium levels (Kovacs, 2011). The challenge of managing hypoparathyroidism in pregnancy is to maintain normocalcaemia in the setting of variable individual responses to calcitriol and calcium supplementation, as well as altered calcium homeostasis.
Inadequate management of hypoparathyroidism during pregnancy can result in miscarriage (Eastell et al., 1985), stillbirth (Callies et al., 1998), preterm labour, and acute neonatal morbidity such as respiratory distress syndrome (Kaneko et al., 1999). Maternal hypocalcaemia can also be complicated by neonatal secondary hyperparathyroidism which in turn causes skeletal demineralization, subperiosteal bone resorption and osteitis fibrosa cystica. Conversely, overtreatment with calcitriol causes maternal hypercalcaemia and suppression of the foetal and neonatal parathyroid glands, and there is the additional concern of teratogenicity using older vitamin D preparations (Roth, 2011).Studies examining the management of hypoparathyroidism in pregnancy and lactation are few, with the majority of data stemming from single case reports. Only two case reports have been published since 2000 (Krysiak et al., 2011 ; Sweeney et al., 2010). The largest case series, published in 1998, described twelve women with maternal hypoparathyroidism (Callies et al., 1998).
Reports thus far have demonstrated that whilst some women have reduced symptoms and decreased calcium and calcitriol requirement during pregnancy, others require increased doses. However, the physiological decline in serum calcium due to haemodilution in pregnancy has sometimes been misinterpreted as worsening hypocalcaemia resulting in the treatment of women based on their laboratory results rather than clinical symptoms (Kovacs, 2011; Eastell et al., 1985; Krysiak et al., 2011; Markestad et al., 1983; Caplan and Beguin, 1990; Rude et al., 1984; Mather et al., 1999; Sadeghi-Nejad et al., 1980 ; Wright et al., 1969). There is consistent evidence that calcitriol requirements decrease during lactation.Monash Health's maternity service is the largest maternity provider in Victoria, Australia, with an associated database that captures birthing outcomes in over 9000 women each year. In this retrospective audit, we outline the available cases and present the results of an audit of the birthing outcomes database, examining ten pregnancies with pre-existing maternal hypoparathyroidism over a fifteen year period.2.
Subjects and methodsEthics approval was obtained from the Monash Health Human Research Ethics Committee to review the Birthing Outcomes System database and identify all pregnancies presenting to the Obstetrics Department between 2000 and 2014 with the concurrent diagnosis of hypoparathyroidism. The diagnosis of hypoparathyroidism was confirmed with the biochemical findings of hypocalcemia and a low serum parathyroid hormone (PTH) level. Subsequent review of medical and biochemical records was performed to record clinical course, treatment, and maternal and foetal outcomes of these pregnancies.3. ResultsThe Birthing Outcomes System database identified twelve pregnancies with pregnancy-associated hypoparathyroidism. Two were excluded due to lack of available data. The remaining ten pregnancies from six women with a diagnosis of hypoparathyroidism will be described.3.1. Cases3.1.1. Pregnancy 1A 37 year old woman attended pre-pregnancy counselling for idiopathic hypoparathyroidism diagnosed two years earlier, following episodic muscle twitching after the birth of her first child.