Intermittent fetal tachycardia and fetal hydrops.

A case is reported where fetal hydrops was noted 10 days after an initial observation of intermittent fetal tachycardia at 31 weeks. A diagnosis of supraventricular tachycardia was made and a successful conversion to sinus rhythm was achieved with maternally administered flecainide, with subsequent resolution of the hydrops. The fetus required no further treatment in pregnancy or at follow up. The mother suffered no side effects of the treatment.