Estradiol

A natural Estrogen that is marketed for oral, injection and topical administration (skin and vaginal). On the chemical form of valerate, it is used in association with a progestin as a combined contraceptive. Estradiol is found naturally in breast milk. ^{(McGarrigle 1983)}

Estradiol is excreted into breast milk in clinically insignificant ^{(Nilson 1978)} or null amounts ^{(Pinheiro 2016, Perheentupa 2004)} and no problems have been observed in infants whose mothers were treated. ^{(Reisman 2018, Pinheiro 2016)}

Plasma levels of these infants were undetectable or very low. ^{(Pinheiro 2016)}

After administration in the form of transdermal patches milk levels have been undetectable. ^{(Pinheiro 2016, Perheentupa 2004)}

Despite these data, an older publication associated the use of transdermal estradiol with a case of jaundice and poor weight gain. ^{(Ball 1999).}

Estrogens, alone or associated with progestogens, have been used in the treatment of excess milk production^{(Johnson 2020)} and to suppress lactation ^{(Piya 2004, Balmer 1971)}, although with very little effectiveness.^{(Kaern 1967)}

There is evidence (albeit inconsistent) that estrogen-containing pills may decrease milk production or the duration of breastfeeding, especially if given during the first few weeks postpartum with a daily dose equal to or greater than 30 micrograms (0,03 mg) diarios. ^{(WHO 2002, AAP 2001, Moretti 2000, WHO 1988, Nilsson 1986, Tankeyoon 1984, Díaz 1983, Peralta 1983, Croxatto 1983, Guiloff 1974, Kaern 1967)}

Treatment with high doses of estrogens during adolescence does not affect later ability to breastfeed. ^{(Jordan 2007)}

The American Academy of Pediatrics states that this medication is usually compatible with breastfeeding. ^{(AAP 2001)}

 

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No short-term or long-term clinical, physical or psychomotor developmental problems have been observed in infants whose mothers were taking combined oral contraceptives ^{(Nilsson 1986)}, except for a few cases published years ago of transient gynecomastia in infants whose mothers were taking a combined oral contraceptive with ethinyl estradiol. ^{(Madhavapeddi 1985, Nilsson 1978, Marriq 1974, Curtis 1964)}

Hormonal contraceptives, both combined and progestogen-only, do not alter the composition of milk, neither in minerals (Mg, Fe, Cu, Ca, P) nor in fats, lactose, proteins or calories. ^{(Urzica 2013, Dórea 2000, 1999 y 1998, Costa 1992)}

No study has found negative effects on breast milk production or infant weight gain when combined oral contraceptives (estrogen + progestin) are started after the first 2, or better 6, weeks postpartum. ^{(Tepper 2015, Espey 2012)}

During lactation progestin-only drugs are preferred or in combination with estrogen for birth control, but whatever, the ones with the lower doses of estrogen should be used. ^{(CDC 2016, 2013 y 2010, WHO 2015, Berens 2015, CLM 2012)}

For the first 6 weeks postpartum, non-hormonal methods are of choise. ^{(Berens 2015, Rowe 2013)}

See below the information of these related products:

• Estradiol + Dienogest (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
• Estradiol + Medroxyprogesterone (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
• Estradiol + Nomegestrol (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
• Estradiol + Norethisterone (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)