Last update April 28, 2026

C18H2O2 + C20H25NO2

Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

Combined oral contraceptive (COC) of estrogen (ethinyl estradiol) and progestogen (norethisterone) in the form of pills for oral use. Daily administration.

For a detailed discussion with references:

  • on why non-hormonal methods are the first choice during the first 4–6 weeks postpartum, followed by IUDs and progestin implants,
  • on the potential problems associated with the use of combined estrogen-progestin contraceptives,
  • the possible decrease in milk production with estrogen use,
  • and why progestin-only contraceptives are preferable during breastfeeding,

see below: “(Combined Estrogen + Progestin Contraceptives, COCs)”

ESTRADIOL is excreted into breast milk in clinically insignificant or null amounts and no problems have been observed in infants whose mothers were treated. Plasma levels of these infants were undetectable or very low. After administration in the form of transdermal patches milk levels have been undetectable. These details, along with references, can be found below under “Estradiol"

DIENOGEST is a progestin with a similar structure as levonorgestrel.

A latest update no published data on excretion into breast milk were found.

Its pharmacokinetic data (high percentage of protein binding and wide volume of distribution) make it highly unlikely that significant quantities will pass into breast milk.

Progestins in general are considered the contraceptives of choice during breastfeeding because they are not significantly excreted in breast milk, do not alter the quantity or composition of breast milk, do not cause side effects, and do not affect the growth and development of infants or the duration of breastfeeding.


See below the information of these related products:

  • (Combined oestrogen-progestogen contraceptives, COCs) (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
  • Dienogest (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)
  • Estradiol (Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.)

Alternatives

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

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José María Paricio, founder of e-lactancia.
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Other names

C18H2O2 + C20H25NO2 is Estradiol + Dienogest in Molecular formula.

Is written in other languages:

Group

C18H2O2 + C20H25NO2 belongs to this group or family:

Tradenames

Main tradenames from several countries containing C18H2O2 + C20H25NO2 in its composition:

Pharmacokinetics

Variable Value Unit
Oral Bioavail. 100/ 91 %
Molecular weight 272 / 311 daltons
Protein Binding 98 / 90 %
VD 1 / 0.55 l/Kg
Tmax 1 - 4 / 1.5 hours
T½ 20 - 26 / 10 - 14 hours
M/P ratio 0.1 -
Theoretical Dose 0.000015 - 0.00015 / ? mg/Kg/d
Relative Dose <0.02 / ? %

References

  1. AEMPS. Estradiol+Dienogest. Ficha técnica. 2025 Full text (in our servers)
  2. Bayer. Estradiol & Dienogest. Drug Summary. 2015 Full text (in our servers)
  3. AAP - American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89. Abstract Full text (link to original source) Full text (in our servers)

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