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 infants exposed in utero to amiodarone.


METHODS
A historic cohort study of gestational exposure to amiodarone was conducted by contacting Canadian cardiac electrophysiologists.


RESULTS
Twelve cases were identified. Of six with first-trimester exposure, one child had congenital nystagmus with synchronous head titubation. There was one case each of transient neonatal hypothyroidism (9%) and hyperthyroidism (9%). A fourth child, exposed to amiodarone from 20 weeks' gestation, had developmental delay, hypotonia, hypertelorism, and micrognathia. Four small-for-gestational-age infants were also exposed to beta-blockers, which in addition to maternal cardiac disease, have been recognized to cause growth restriction. beta-Blockers may also have contributed to bradycardia in one of the three fetuses in whom this was observed.


CONCLUSIONS
Gestational exposure to amiodarone may be complicated by perinatal hypothyroidism or hyperthyroidism and possibly neurologic abnormalities, intrauterine growth retardation or fetal bradycardia. Concomitant beta-blocker therapy should probably be avoided. Full neonatal thyroid function tests and developmental follow-up are recommended.
Magee
L A
LA
Division of Clinical Pharmacology/Toxicology, Hospital for Sick Children, Toronto, Ontario, Canada.
Downar
E
E
Sermer
M
M
Boulton
B C
BC
Allen
L C
LC
Koren
G
G
D000319:Adrenergic beta-Antagonists / Q000009:adverse effects; D000328:Adult; D000638:Amiodarone / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001919:Bradycardia / Q000139:chemically induced; D002170:Canada; D015331:Cohort Studies; D005260:Female; D005315:Fetal Diseases / Q000139:chemically induced; D005317:Fetal Growth Retardation / Q000139:chemically induced; D006801:Humans; D006980:Hyperthyroidism / Q000139:chemically induced; D007037:Hypothyroidism / Q000139:chemically induced; D007231:Infant, Newborn; D009422:Nervous System Diseases / Q000139:chemically induced; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy*; D011256:Pregnancy Outcome; D011297:Prenatal Exposure Delayed Effects; D012189:Retrospective Studies; D012307:Risk Factors
D000319:Adrenergic beta-Antagonists; D000638:Amiodarone