: The most common tachyarrhythmias in fetal cases is supraventricular tachycardia (SVT); atrioventricular nodal re-entrant tachycardia (AVNRT) type. Premature delivery, neonatal complications, and mortality following fetal SVT are high, and therefore, require proper management. Hereby, we introduce an AVNRT that was diagnosed in the fetus and adenosine infusion, and propranolol tablets were initially administered, but arrhythmia was not controlled; eventually, the tachycardia was controlled with flecainide tablets. She was discharged with the prescription of propranolol and flecainide tablets. She is currently 18 months old and under follow-up.