Pharmacologic treatment of hyperthyroidism during lactation.
OBJECTIVE
I have a patient who has hyperthyroidism due to Graves disease. She was taking methimazole but discontinued when she found out she was pregnant. She is currently close to delivery and might require antithyroid therapy in the postpartum period. Can methimazole cross into human milk, and is breastfeeding safe for her infant?


CONCLUSIONS
The exposure of infants to methimazole or propylthiouracil through breast milk is minimal and not clinically significant. Women with hyperthyroidism using methimazole or propylthiouracil should not be discouraged from breastfeeding, as the benefits of breastfeeding largely outweigh the theoretical minimal risks.
Glatstein
Miguel Marcelo
MM
Garcia-Bournissen
Facundo
F
Giglio
Norberto
N
Finkelstein
Yaron
Y
Koren
Gideon
G
D013956:Antithyroid Agents / Q000009:adverse effects / Q000032:analysis*; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy*; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation; D018811:Maternal Exposure; D008713:Methimazole / Q000009:adverse effects / Q000032:analysis* / Q000627:therapeutic use; D008895:Milk, Human / Q000737:chemistry*; D011247:Pregnancy; D011441:Propylthiouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000032:analysis*; D013961:Thyroid Gland / Q000187:drug effects; D016896:Treatment Outcome
D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil
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