drugs
Risk Factors for Adverse Drug Reactions
Pregnancy and Breastfeeding
 receptor blockers (ARBs)—pose a risk to the health and normal development of a fetus. To the extent possible, pregnant women should not take any drugs, especially during the first trimester (see table Some Drugs That Can Cause Problems During Pregnancy* . However, for some medications, including ACE inhibitors and ARBs, risk increases during the second and third trimesters of pregnancy. Use of any prescription medications, Medications and medicinal herbs may be transmitted through breast milk to an infant (see Medication and Substance Use During Breastfeeding ). Some drugs should not be taken by women who are breastfeeding, whereas others can be taken but require a doctor's supervision. Some drugs do not usually harm the breastfed infant. However, women who are breastfeeding should consult with a health care practitioner before they take any drugs. Social and illicit drugs may harm a breastfeeding infant. 