Primary Hyperparathyroidism Diagnosed during the Work-up of Hydrops Fetalis : A Case Report

While rare in pregnancy, unrecognized primary hyperparathyroidism (PHPT) may pose significant risks to both maternal and fetal health. While the majority of non-pregnant individuals are diagnosed incidentally with PHPT after routine laboratory screening, serum calcium levels are not routinely ordered in pregnancy and many expectant mothers may go undiagnosed. We present a case of non-immune hydrops and fetal demise diagnosed at 25 weeks gestation in a 24 year-old primigravida. Her workup for hydrops fetalis was negative other than an elevated calcium level which was incidentally noted on routine lab-work, low phosphorus, and elevated parathyroid hormone. Following delivery of a non-viable fetus, ultrasound and Sestamibi scans confirmed the presence of a parathyroid adenoma, which was later removed surgically. The literature suggests that fetal and maternal complication rates from PHPT are high. Fetal complications include preterm birth, stillbirth, and growth restriction. Fetal demise in PHPT occurs at 3.5 times the known rate of pregnancy loss in the general population. Symptomatic PHPT can be safely managed during pregnancy with parathyroidectomy ideally occurring in the second trimester.