Melatonin

Hormone secreted by Pineal gland which exerts its function by regulating the Circadian pattern of sleeping. It is naturally found in the mother's milk. ^{(Cohen 2012)}

Melatonin has a circadian rhythm. The level of Melatonin in the plasma and breast milk, nearly undetectable during the day, increases by night ^{(Gombert 2021,Italianer 2020, Katzer 2016, Cohen 2012, Illnerová 1993)}. It is believed that this helps to organize the sleep - awake cycle in breastfed newborns and infants. ^{(Sánchez 2011)}. The older the mother, the less melatonin is in breast milk ^{(Gila 2020)}. Melatonin levels are maintained in frozen breast milk. (Molad 2019)

It has antioxidant and anti-inflammatory properties ^{(Gombert 2021,Tan 2014)}, and, it is found in many foods, either vegetable or animal in origin (meat, fish), eggs, wine and beer. ^{(Tan 2014)}

On latest update, no relevant published data related to breastfeeding were found.

Known side-effects of melatonin are mild and few ^{(Andersen 2016)}. It is being used for co-treatment of several conditions in chidren, newborn infants and prematures ^{(Gitto 2013, Merchant 2013, Sánchez 2011)} with good tolerance in spite of higher doses than those excreted in the breast milk.

Its very low oral bioavailability ^{(EMA 2012, Fourtillan 2000, DeMuro 2000)} minimizes the passage into plasma of the infant from ingested breast milk, except in the premature and in the immediate neonatal period in which there may be greater intestinal permeability.

Expert authors consider the use of this medication possible during breastfeeding. ^{(Hale, LactMed, Vine 2021)}