PREGNANCY OUTCOME AFTER GESTATIONAL EXPOSURE TO AMIODARONE IN CANADA

OBJECTIVE: Our purpose was to quantitate the risk of perinatal thyroid dysfunction and other amiodarone-induced adverse effects among infant s exposed in utero to amiodarone. STUDY DESIGN: A historic cohort stud y of gestational exposure to amiodarone was conducted by contacting Ca nadian cardiac electrophysiologists. RESULTS: Twelve cases were identi fied. Of six with first-trimester exposure, one child had congenital n ystagmus with synchronous head titubation. There was one case each of transient neonatal hypothyroidism (9%) and hyperthyroidism (9%). A fou rth child, exposed to amiodarone from 20 weeks' gestation, had develop mental delay, hypotonia, hypertelorism, and micrognathia. Four small-f or-gestational-age infants were also exposed to beta-blockers, which i n addition to maternal cardiac disease, have been recognized to cause growth restriction. beta-Blockers may also have contributed to bradyca rdia in one of the three fetuses in whom this was observed. CONCLUSION S: Gestational exposure to amiodarone may be complicated by perinatal hypothyroidism or hyperthyroidism and possibly neurologic abnormalitie s, intrauterine growth retardation or fetal bradycardia. Concomitant b eta-blocker therapy should probably be avoided. Full neonatal thyroid function tests and developmental follow-up are recommended.