Animal studies have revealed evidence of fetal and neonatal toxicity and mortality. There are no controlled data in human pregnancy.

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.

This drug should not be used during pregnancy unless there are no alternatives and the benefit outweighs the risk to the fetus; use is contraindicated during the second and third trimesters per some authorities.

US FDA pregnancy category: Not assigned.

Risk Summary: Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death.

Comments: Adequate methods of contraception should be encouraged.

See references

Use is not recommended and a decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (hydrochlorothiazide); Unknown (losartan)
Excreted into animal milk: Yes (losartan)

See references