Management of Chronic Hypoparathyroidism and Hyperparathyroidism in Pregnancy/Lactation

We summarize and discuss evidence on management of chronic hypoparathyroidism (HypoPT) and primary hyperparathyroidism (PHPT) in pregnancy and lactation to provide guidance for clinical care.

Women with HypoPT are at increased risk of certain pregnancy complications, though most pregnancies are uncomplicated. Conventional therapy with activated vitamin D and calcium is continued throughout pregnancy, but there are unpredictable changes in the required dosages warranting regular surveillance during pregnancy (e.g., all 3 to 4 weeks). Data on parathyroid hormone (PTH) replacement therapy in pregnancy are limited, but a few case reports suggest favourable outcomes with this treatment. During lactation, dosage requirements for conventional therapy of HypoPT are often reduced and usually normalize again after weaning. In women with PHPT, surgical treatment should be pursued before conception. PHPT is not associated with adverse pregnancy outcomes in women with mild hypercalcemia but maternal and fetal complications significantly increase with higher calcium concentrations. There is no clear threshold for this risk increase, but several studies and expert groups support a cut-off concentration of about 2.85 mmol/L in albumin-adjusted calcium and 1.45 mmol/L in ionized calcium. For pregnant women with PHPT and calcium above these cut-off concentrations, parathyroidectomy, preferentially in the second trimester, is recommended. Medical treatment for hypercalcaemic PHPT is limited and requires individual decision making. Immediately after delivery, hypercalcemia may worsen in women with PHPT. Clinical care of women with HypoPT and PHPT in pregnancy and lactation requires intensive surveillance and consideration of the specific changes in bone and mineral metabolism during these times.