Pregnancy may trigger cardiac arrhythmias that have not previously been observed in apparently healthy individuals. The risk of arrhythmias is relatively higher during labor. Potential factors that may contribute to arrhythmias during pregnancy and labor include direct electrophysiological effects of hormones on the heart, changes in autonomic tone, hemodynamic disturbances, hypokalemia of pregnancy, and concomitant cardiac disease. Paroxysmal supraventricular and ventricular tachycardia may cause hemodynamic disturbances with consequences for the fetus. Treatment of arrhythmias in pregnant women is similar to that in non-pregnant women, but special attention should be paid to avoid adverse effects on the fetus.