The management of common medical problems in pregnancy often requires adjustments in drug therapy to assure a healthy fetus. The management of steroid-dependent bronchial asthma in pregnancy requires oxygen supplementation as well as vigorous treatment of airway obstruction to protect the fetus from maternal hypoxemia. The hypertensive pregnant patient should discontinue dietary sodium restriction and diuretic therapy and should be managed with alphmethyldopa or beta-blocker therapy. Hydralazine may be added if hypertension is severe. Mitral valve prolapse appears to produce no difficulties during pregnancy and the use of prophylactic antibiotics is probably not necessary for routine vaginal delivery, unless complications occur. Digoxin and quinidine are safe to use in pregnancy, provided careful monitoring is maintained. Oral anticoagulants are contraindicated in pregnancy and should be replaced with heparin if pregnancy is desired.