Women are advised against taking ACE inhibitors during pregnancy, especially during the second and third trimesters but also in the first trimester. The medication can cause low blood pressure, severe kidney failure, hyperkalemia (too much potassium in the blood), or death or deformity of the newborn. Patients taking ACE inhibitors should inform their physician immediately if they become pregnant, or are planning to become pregnant, so they can start alternative therapy to ACE inhibitors.

When breastfeeding, some ACE inhibitors will pass into breast milk. Although this has not been found to cause problems in nursing infants, an alternative feeding method is recommended when ACE inhibitors are being used.