Incidence of MEN1 syndrome is 1/30,000 in general population and incidence of primary hyperparathyroidism (PHPT) in reproductive age women is 8/100,000 population/year. However, coexistent of MEN1, PHPT and pregnancy is extremely rare and true incidence is unknown.
Despite improvements in medical and obstetric care, PHPT in pregnancy remains high risk pregnancy with significant morbidity and mortality.
Case 1: confirmed MEN1 gene mutation with previous distal pancreatectomy for neuroendocrine tumour; was diagnosed to have PHPT during her second pregnancy at age 26 years. Her adjusted calcium was 2.71 (2.2 2.6 mmol/L). She remained asymptomatic and was managed conservatively during pregnancy. She delivered healthy boy at 39 weeks gestation. During post-partum period, she underwent parathyroid surgery.
Case 2: younger sister of case 1, with PHPT diagnosed age 14 years and confirmed MEN-1 gene mutation had previously declined parathyroid surgery. At age 28 years, during her first pregnancy adjusted Calcium was 2.88 mmol/L. The management plan including parathyroid surgery was discussed. However she declined surgery due to concerns related to anaesthetic risk mainly increased risk of fetal loss.
At 20 weeks gestation, fetal growth was below 5th centile. Further scan 3 days later confirmed reduced blood flow in umbilical cord with abnormal umbilical artery Doppler PI. Despite close monitoring, adequate hydration, her calcium remained high and she developed pregnancy induced hypertension. The need for Parathyroid surgery was revisited however she declined. Unfortunately, at 24 weeks gestation, fetal scan confirmed intrauterine death.
PHPT in pregnancy is associated with increased maternal (67%) and fetal (80%) complications. Maternal complications include gestational hypertension, pre-eclampsia, nephrolithiasis, bone disease, pancreatitis, hyperemesis, mental status changes, and hypercalcaemic crisis. Fetal complications include intrauterine growth retardation, low birth weight, preterm delivery, intrauterine fetal demise, postpartum neonatal tetany, and permanent hypoparathyroidism.
These 2 cases highlight the fact that PHPT remains high risk and conservative intervention may be appropriate under certain circumstances, however excision of a parathyroid adenoma remains the only definitive treatment.