This study was designed to examine the teratogenic potential of copper releasing intrauterine contraceptive devices on the developing embryo. The tissues and organs of 11 whole embryos between 7 and 12 weeks of gestation were histologically examined for copper absorption after exposure to a copper intrauterine device in utero. The findings were not significantly different when compared with a control group of 7 embryos. No malformation or copper aggregates were observed in the various organs and placentas. The observations in this small sample would suggest that the copper-releasing intrauterine device has no deleterious effects on fetal development. The question remains whether malformations reported in some cases are associated with copper deposits in the tissues or with free copper ions in the fetal circulation. The implications are discussed.