Animal studies showed urogenital malformations with high doses of maternal estrogen, and masculinization of female fetuses with high dose progestogens, but relevance to clinical use of estradiol is uncertain. There are no controlled data in human pregnancy. A limited number of pregnancies showed masculinization of female fetuses at doses of norethindrone at doses higher than normally used for oral contraception or hormone replacement therapy. There appears to be little or no increased risk of birth defects when estrogens and progestins as oral contraceptives were inadvertently used during early pregnancy.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

Use is contraindicated. (AU, US)
Use is not indicated during pregnancy (UK)

AU TGA pregnancy category: D
US FDA pregnancy category: Not assigned

Comments:
-If pregnancy occurs, discontinue treatment immediately.

See references

Use is contraindicated. (AU)
Use is not recommended. (UK, US)

Excreted into human milk: Yes

Comments:
-Estrogen use during lactation has been shown to decrease the quantity and quality of breast milk.
-Detectable amounts of estrogens and progestins have been found in breast milk.

See references