Tamoxifen Pregnancy and Breastfeeding Warnings

Brand names: Emblon, Genox, Nolvadex, Nolvadex D, Soltamox, Tamofen, Tamone, Tamosin, Tamoxen, Tamoxifen Hexal

Medically reviewed by Drugs.com. Last updated on Jun 13, 2025.

Tamoxifen Pregnancy Warnings

Use is contraindicated.

AU TGA pregnancy category: B3
US FDA pregnancy category: Not assigned

Risk summary: This drug may cause fetal harm when administered to a pregnant woman. In animal studies, it increased embryotoxicity, abortions, and altered learning behaviors at doses less than or equal to human dose.

Comments:
-Women should be advised not to become pregnant while taking this drug or within 2 months of discontinuing therapy and should use barrier or nonhormonal contraceptive measures if sexually active.
-If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.

Animal studies of doses at or below equivalent human doses have revealed evidence of fetotoxicity, lower incidence of implantation, and an increased incidence of low birth weight. There are no controlled data in human pregnancy; however, the manufacturer reports spontaneous abortions, birth defects, fetal deaths, and vaginal bleeding associated with this drug during pregnancy.

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

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.

See references

Tamoxifen Breastfeeding Warnings

Breastfeeding is not recommended during use of this drug.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

Comments:
-This drug can suppress postpartum lactation and should be avoided in nursing mothers.

See references

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer