Below is a summary of recommendations regarding medications used for various endocrine conditions.

For more detailed information and references on specific medications, please refer to Lactmed, e-lactancia, Infant Risk, or Mother to Baby.

• Hypothyroidism: T4 Analogs (Synthroid/levothyroxine, T3 Analogs (Triostat/liothyronine), Mixed T3/T4 (Armour Thyroid/desiccated thyroid extract). Thyroid hormones are normal components of breastmilk and are considered safe in the breastfeeding dyad. According to the 2017 Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and postpartum, it is recommended to treat subclinical and overt hypothyroidism during lactation (1). There is no absolute indication to pump and dump.
• Hyperthyroidism: These medications are generally considered safe during lactation with the exception of propylthiouracil and radioiodine (I 131)
  • Symptomatic treatment with beta blocking medications: These medications can be used to control symptoms in the hyperthyroid state. There is no absolute indication to pump and dump. For more information, see the section on Blood Pressure Medications.
  • Antithyroid (thionamides): With these medications there is a theoretical risk for blood abnormality such as agranulocytosis. If this is suspected, the nursing infant’s blood count and differential should be monitored (2). No special thyroid surveillance or growth monitoring is required for the nursing infant outside of routine well child exams. While the infant should be closely monitored for side effects (such as increased infections associated with agranulocytosis) with use of this class of medications by a lactating individual, there is no absolute indication to pump and dump and shared decision making should be used with these medications.
    • Methimazole/Tapazole: When used in doses up to 20mg daily, there have not been found to be any negative short- or long-term effects in the nursing infant (2-4). While the infant should be closely monitored for side effects (such as increased infections associated with agranulocytosis) with use of this medication by a lactating individual , there is no absolute indication to pump and dump and shared decision making should be used with these medications.
    • Propothiouracil/Halycil: There is a theoretical risk of this medication causing liver damage in the nursing infant, but there have been no reports of this in available literature. For this reason, methimazole is preferred during lactation. Dosing of this medication is recommended to be limited to 450mg daily if alternatives cannot be used (1). Alternative medications should be considered due to the theoretical risk of liver damage for the breastfeeding infant.
    • Carbimazole (metabolized to methimazole): This medication is not available in the US and is a prodrug of methimazole. Dosing of this medication 30mg daily or 50mg weekly has not been found to have any harmful effects in the nursing infant. While the infant should be closely monitored for side effects (such as increased infections associated with agranulocytosis) with use of this medication by a lactating individual, there is no absolute indication to pump and dump and shared decision making should be used with these medications.
  • Radioiodine (Sodium Iodine 131, I 131): This medication, for diagnostic and therapeutic purposes, is not safe in the breastfeeding dyad. To avoid concentration of this medication in the breast tissue, it is recommended to completely wean the infant 4-6 weeks prior to administration of this drug (5-7). It is also recommended to avoid close contact of the infant with the treated individual after this medication is administered anywhere from 15-27 days depending on the indication (8). The American Thyroid Association recommends the use of I-123 or Tc99m pertechnetate scans for diagnosis of hyperthyroidism during lactation as an alternative if imaging is warranted (1). Due to the nature of this medication, either thioamides or surgery may be preferred if the mother wishes to continue nursing her infant in the setting of hyperthyroidism. Lactating individuals should pump and dump with the use of this medication.
  • Thyroid Storm
    • Glucocorticoids (Hydrocortisone 100mg IV q8hr): Glucocorticoids are naturally occurring in breast milk. At high doses, glucocorticoids can cause transient decrease in milk production. Glucocorticoids that have been more extensively studied during lactation (methylprednisolone, prednisolone, prednisone) may be preferred until more information is known. While lactating individuals should be informed of the risks to milk production with high doses of glucocorticoids, there is no absolute indication to pump and dump. For more information, see the section on Steroids.
    • Bile acid sequestrants (cholestyramine): It does not enter the mother’s blood stream, and therefore will not enter the breastmilk. There is no absolute indication to pump and dump.

• Dopamine Agonist (cabergoline, bromocriptine/Cyclocet/Parlodel, quinagolide/Norprolac): These medications will lead to near or complete loss of milk production so they are generally not used during lactation. While lactating individuals should be informed of the risks to milk production, there is no absolute indication to pump and dump.
• Inadequate Responses or intolerance to other medications
  • Clomid: Risks and benefits should be discussed with the patient. The use of clomid has been shown to suppress lactation and can decrease milk production. Theoretical risks to the infant also exist. Shared decision making should be used with this medication regarding whether to pump and dump. For more information, please see the section on Infertility Medications.
  • Letrozole: The manufacturer of letrozole recommends nursing cessation with use of this drug. There is no information about letrozole use during lactation. In one mother who provided 8 milk samples over 24 hours, the relative infant dose of letrozole was found to be 10.2% (9). Lactating individuals should pump and dump while taking this medication and for 10 days after the last dose. For more information, please see the section on Infertility Medications.
  • Estrogen/progesterone: Estrogen can reduce milk production. While lactating individuals should be informed of the risk to milk production, there is no absolute indication to pump and dump. For more information, see the section on Contraceptives.

• Supplements: Generally, the supplements discussed below are considered safe in the breastfeeding dyad but the ingredients of specific supplements should be verified to ensure they are compatible with lactation. These supplements are normal components of breastmilk, and little data has been gathered about exogenous supplementation while breastfeeding. There is no absolute indication to pump and dump.
  • Calcium: There is no absolute indication to pump and dump.
  • Vitamin D: Maternal supplementation at or above 6400 IU may be sufficient to meet infant requirements of 400 IU daily. There is no absolute indication to pump and dump.
• Anti-resorptive agents
  • Bisphosphonates (alendronate/Fosamax, risedronate/Actonel, ibandronate/Boniva, zoledronic acid/Reclast): Little to no data is available for this class of medications. However, due to poor oral absorption of these medications, infant absorption of these medications is unlikely. There is no absolute indication to pump and dump.
  • Denosumab/Prolia: There is no data available on the use of this medication during breastfeeding. This medication is a monoclonal antibody and is a very large peptide protein such that the medication concentration in breastmilk is suspected to be low. Due to the nature of being a peptide molecule, the small amount that may enter the breast milk would likely be destroyed by the infant’s gastrointestinal tract and not be absorbed by the infant. There is no absolute indication to pump and dump.
  • Selective estrogen receptor modulators (raloxifene/Evista): There is no data available on the use of this medication during breastfeeding. This medication has poor oral absorption (2%), therefore the amount in the breastmilk and thus absorbed by the infant is likely low enough to not cause adverse infants side effects. A short course of this medication is likely safe in the breastfeeding dyad until more data is known. There is no absolute indication to pump and dump.
  • Estrogen/progesterone therapy: Estrogen can reduce milk production. While lactating individuals should be informed of the risk to milk production, there is no absolute indication to pump and dump. For more information, see the section on Contraceptives.
• Anabolic agents
  • Parathyroid hormone/parathyroid hormone-related analog (teripartide/Forteo, abaloparatide/Tymlos): There is little or no information available on the use of these medications during breastfeeding. Due to their high molecular weight, rapid metabolism, and low oral bioavailability, breastfeeding infants are unlikely to be exposed to these medications in clinically significant amounts. Monitoring infant serum calcium may be appropriate with use of these medications, especially in newborns and premature infants. While infants may need to be monitored for side effects, there is no absolute indication to pump and dump.
  • Romosozumab/Evenity: There is no information available on the use of this medication during breastfeeding. This medication is a monoclonal antibody and is a very large peptide protein such that the medication concentration in breastmilk is suspected to be low. Due to the nature of being a peptide molecule, the small amount that may enter the breast milk would likely be destroyed by the infant’s gastrointestinal tract and not be absorbed by the infant. There is no absolute indication to pump and dump.

• Glucocorticoids (Hydrocortisone, Prednisone, dexamethasone): There is no absolute indication to pump and dump. For more information, see the section on Steroids.
• Mineralocorticoids (fludocortisone/Florinef): This oral medication is a derivative of hydrocortisone. The glucocorticoid effect of this medication is 15x more potent than hydrocortisone. No data is available for this medication; however, it is unlikely that the amounts in breastmilk are clinically high enough to cause adverse infants side effects at usual dosing. There is no absolute indication to pump and dump. For more information, see the section on Steroids.
• Androgen Replacement (DHEA, DHEAS): DHEA supplementation should be avoided in lactating individuals. This supplement can decrease milk production and the risk to the infant via possible exposures in breastmilk is unknown. There is a lack of data regarding milk transfer of DHEA and its metabolites. Due to a lack of data regarding safety and possible risk to the infant, this supplement should be avoided in lactating individuals.

• Metformin: There is no absolute indication to pump and dump. For more information, see the section on Diabetes Medications.
• Oral Contraceptives: While lactating individuals should be informed of the risk to milk production, there is no absolute indication to pump and dump. For more information, see the section on Hormonal Contraceptive Medications in Contraceptives.
• Spironolactone: There is no absolute indication to pump and dump. For more information, see the section on Acne Medications.

For more information, see the section on Diabetes Medications.