Life span: Pregnant or breast-feeding women

• Drug therapy may be indicated for pregnant or lactating women to manage preexisting or newly developed conditions. Although therapeutic effects may be achieved in the woman, drug therapy may adversely affect the fetus or infant. • The physiologic changes that occur during pregnancy may alter drug absorption, distribution, and elimination. • Some drugs are contraindicated in pregnancy, and caution is advised for using others because drugs may pass through the placenta to the fetus and cause teratogenic effects. The potential fetal risks must be compared with maternal benefi ts when drug therapy is required. • The effects of most approved drugs on a developing human fetus are not known. Voluntary enrollment by pregnant women in Pregnancy Registries for different drug therapies is one new mechanism for gaining knowledge about drugs and their effects on the developing fetus. • Drugs may be excreted into breast milk, although the total received by the infant is a small percentage of the maternal dose. The nurse should be familiar with the prescribed drugs and the substances of abuse that are contraindicated during breast-feeding. • Symptoms of pregnancy may mask adverse effects of drug therapy in the mother. Discomforts commonly associated with pregnancy, such as nausea and vomiting, light- headedness or hypotension, constipation, heartburn, urinary frequency, heart palpitations, and fatigue, are also frequent adverse drug effects. • Limiting drug use during pregnancy and lactation decreases maternal and fetal adverse effects. Nonpharmacologic alternatives to drug therapy should be used if possible, particularly when treating the common discomforts of pregnancy. • Substances of abuse are contraindicated during pregnancy and lactation because they can cause serious teratogenic effects, such as fetal alcohol syndrome, or harm the breastfeeding infant. • The minimum therapeutic dose should be used for as short a time as possible during pregnancy. If possible, drug therapy should be delayed until after the fi rst trimester of pregnancy, during which the fetal organ systems are forming. • Both the pregnant patient and the fetus should be monitored for therapeutic and adverse effects of drug therapy, and that practice should continue for the lactating patient and breast-feeding infant.