We report two cases of supraventricular tachycardia, diagnosed and treated in the prenatal period. The first case concerns a fetus diagnosed with supraventricular tachycardia in week 31 of gestation. The mother was treated with digoxin with subsequent addition of propranolol. Although cardioversion was not achieved, the fetus showed no signs of cardiac decompensation. The second case involved a fetus diagnosed with supraventricular tachycardia with hydrops and polyhydramnios at week 28+3 of gestation. The mother was treated with digoxin and flecainide was subsequently added, achieving sinus rhythm.