Association of drug treatments in pregnant women with the risk of external ear congenital abnormalities in their offspring: a population-based case-control study.

The objective of this study was to evaluate the possible association of drug treatments in pregnant women with a higher risk of congenital abnormalities of the external ear, particularly microtia/anotia, in their children. The frequency of drug treatments was compared in the mothers of cases with isolated or multiple (syndromic) ear abnormalities and in the mothers of three different controls: controls matched to cases, all controls (these controls had no defects) and malformed controls in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities. There was no significantly higher use of any drug in the mothers of 354 cases with isolated external ear abnormalities than in the mothers of different controls. However, of 156 cases with multiple ear abnormalities, 11 had mothers with hydroxyethylrutosidea treatment and a characteristic pattern of congenital abnormalities was found in these children. Four cases with multiple ear abnormalities were born to epileptic mothers treated with valproate, phenytoin and polytherapy in two cases. Drug treatments are not important in the origin of isolated ear abnormalities. However, a higher risk of multiple ear abnormalities was found in children born to mothers with treatment of hydroxyethylrutosidea or antiepileptic drugs during pregnancy.