During pregnancy physiological mechanisms of adaptation of maternal organism affect a course of chronic hypoparathyroidism (HypoPT) that needs close monitoring to avoid the maternal and fetal complications. We present a case of management of postsurgical (PS) HypoPT during gestation and lactation.

A 31-year-old female took levothyroxine sodium 125mcg/day, alfacalcidol 1mcg/day, calcium carbonate 750mg/day and cholecalciferol 15000IU/week after thyroidectomy and radioiodine therapy for papillary cancer T1N1M0. This treatment allowed maintaining a compensation of PS hypothyroidism and HypoPT during the pre- and interpregnancy intervals. The first pregnancy in 3 years after surgery and 1-year follow-up lactation was successfully managed with calcium carbonate 1500mg/day and cholecalciferol 20000IU/week without vitamin D analogs. When the second pregnancy occurred alfacalcidol was initially discontinued by the patient herself, she took calcium carbonate 750mg/day, cholecalciferol 2000IU/day and levothyroxine 137mcg/day. At 26 weeks of the gestation the woman went to a specialized center with complaints of persistent seizures, lab tests showed hypocalcemia (total serum calcium (Ca) 1.84mmol/L (2.15-2.55), ionized Ca 1.08mmol/L (1.18-1.32)) and hypomagnesemia (0.64mmol/L), TSH 1.85mU/L. 

The patient was administrated alfacalcidol in start dose of 1mcg/day, magnium lactate 300mg/day, dose of calcium carbonate increased to 1500mg/day with close control of lab parameters and correction of therapy every week. The complete compensation of HypoPT was achieved at 30 week (albumin adjusted Caadj 2.13mmol/L, P 1.25mmol/L (0.74-1.52), 25OHD 54.9ng/mL) when she took alfacalcidol 2.5mcg/day, calcium carbonate 2000mg/day. Cesarean section was performed at 40 week without serious complications in the mother and newborn. During breastfeeding initiation hypercalcemia (Caadj. 2.8mmol/L) was detected and all drugs were cancelled, except levothyroxine. Hypercalcemia (Caadj 2.54-2.65 mmol/L) persisted for 5 months of lactation until normalization and then standard therapy of HypoPT was resumed.

HypoPT in pregnancy and lactation needs the personalized approach to treatment. Regular monitoring of lab parameters and dynamic therapy adjustment are recommended to optimize maternal and fetal outcomes.

Ekaterina Bibik is an endocrinologist, PhD, and a researcher at the Department of Parathyroid Pathology and Mineral Disorders at the Endocrinology Research Centre, Russia. She has over 60 publications with more than 250 citations, and her publication h-index is 8.