Calcitriol and Breastfeeding

Summary of use during lactation

Calcitriol is the normal physiologically active form of vitamin D, 1,25-dihydroxyvitamin D. Several women with hypocalcemia have successfully breastfed during breastfeeding, with sometimes fluctuating serum calcium levels. Limited data indicate that its use in nursing mothers in appropriately adjusted doses does not affect the breastfed infant. If the mother requires calcitriol, it is not a reason to discontinue breastfeeding. Calcitriol and calcium dosage requirements are usually reduced during lactation in women with hypoparathyroidism and failure to reduce doses can lead to hypercalcemia.[1-14]

Drug levels in milk and infant serum

Maternal Levels. Relevant published information was not found as of the revision date. Infant Levels. Relevant published information was not found as of the revision date.

Effects in breastfed infants

A woman with hypoparathyroidism breastfed her infant from week 1 to week 32 postpartum while taking calcitriol. The dose was initially 0.5 mcg daily, but was decreased to 0.25 mcg daily after 8 weeks. The infant thrived during breastfeeding and had normal serum calcium levels at 1 and 3 weeks and 3 months of age.[3] A woman breastfed infants after two pregnancies while taking calcitriol in doses of 0.75 and 1 mcg daily. There were no reports of adverse reactions.[15] A woman breastfed her newborn infant for 9 days while taking calcitriol 0.5 mcg three times daily. Calcitriol was stopped at that time because of hypercalcemia, but restarted at 40 days postpartum in low doses that were gradually increased until the prepregnancy dosage of 1.5 mcg daily was reached just before weaning at 12.5 months postpartum.[5] A woman with discoid lupus was taking calcitriol 0.25 mcg every 2 days and several other medications concurrently. Her infant was breastfed for 12 months and followed up at 15 months of age. No adverse effects were reported during breastfeeding and the infant was growing and developing normally at 15 months of age.[16] A nursing mother with autosomal dominant hypoparathyroidism type 1 was treated with teriparatide for 8 months postpartum then calcitriol 0.5 mcg twice daily was substituted. She breastfed her infant exclusively for 6 months then with supplementation to 1 year. Her infant had no change in serum calcium when maternal calcitriol was begun. The mother began weaning at 11 months and at 1 year of age weaning was complete. Growth and development were normal at 1.5 years of age. [11] A mother had a total parathyroidectomy after noticing neck swelling during pregnancy. After the surgery she experienced symptoms of hypocalcemia. She was started on elemental calcium 4 grams daily and calcitriol 0.5 mcg twice a day, which resolved her symptoms. She began breastfeeding and one week after discharge, she had a serum calcium of 12.4 mg/dL. Calcium supplementation was stopped and her serum calcium normalized.[14]

Effects on lactation and breastmilk

Relevant published information was not found as of the revision date.

References

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14. Davis B. Iatrogenic hypercalcemia during lactation in a patient with postsurgical hypoparathyroidism. 2025;31:S28. doi:10.1016/j.eprac.2025.05.084
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