In: Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006.


Hydrocortisone (cortisol) is a normal component of breastmilk, but it has not been studied in milk after exogenous administration in pharmacologic amounts. Although it is unlikely that dangerous amounts of hydrocortisone would reach the infant, a better studied corticosteroid might be preferred. Maternal use of hydrocortisone as an enema would not be expected to cause any adverse effects in breastfed infants. Local maternal injections, such as for tendinitis, would not be expected to cause any adverse effects in breastfed infants. Medium to large doses of corticosteroids given systemically or injected into joints or the breast have been reported to cause temporary reduction of lactation. See also Hydrocortisone, Topical.

Cortisol in breastmilk might have a role in intestinal maturation, the intestinal microbiome, growth, body composition or neurodevelopment, but adequate studies are lacking.[1] Concentrations follow a diurnal rhythm, with the highest concentrations in the morning at about 7:00 am and the lowest concentrations in the late afternoon and evening.[2,3] Cortisol concentration in milk also increase with infant age and decrease with complementary feeding and infant illness.[4] Cortisol in milk may protect against later infant obesity, especially in girls;[5] however, in another study, milk glucocorticoid levels were positively associated with percent fat mass, adiposity and head circumference at 1 year of age.[6] Maternal stress can increase breastmilk cortisol levels, especially with preterm births.[7,8] Some information indicates that maternal adverse childhood experiences may decrease cortisol concentration in their breastmilk.[9]

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