One of the most difficult decisions for women suffering from a chronic or recurrent illness is whether or not to continue taking maintenance medications during pregnancy. As with nonpsychiatric disorders, pregnancy may either ameliorate or worsen pre-existing symptoms of illness. For instance, the rate and severity of depression appear to be similar in pregnant and nonpregnant women but panic disorder improves in pregnancy. As the treatment of psychiatric disease improves, more women with psychiatric conditions will become pregnant. The pros and cons of psychotropic drugs in breast-feeding women with mental illness are complicated by the fact that essentially all psychiatric disorders worsen in the postpartum period. Effective treatment at this vulnerable time is essential. Untreated illness in new mothers could lead to hospitalization and mother-child separation, deleterious for both. The pregnant mother needs to be carefully monitored and nonpharmacological treatments are to be preferred whenever possible.