The majority of women with bioprosthetic valves do not require anticoagulation during pregnancy. In women with mechanical valves, a detailed discussion of the advantages and disadvantages of the three anticoagulant options (warfarin, unfractionated heparin and low molecular weight heparin) is indicated. The majority of women with arrhythmias during pregnancy have a benign increased rate of atrial or ventricular premature beats. Those women who are hemodynamically stable can be reassured and do not usually require treatment. Women with more ominous arrhythmias should be managed in collaboration with a cardiologist, usually using the same agents that would be chosen in the non-pregnant patient, including electrical cardioversion when necessary. This is the fifth and final article in a series reviewing in detail the assessment and management of specific cardiac disorders in pregnancy.