Congenital malformations of the auditory apparatus induced by hypervitaminosis A in rat foetuses

Abstract

Malformations of the external ear invariably associated with those of middle and internal ear were reported in 20 day rat fetuses, following maternal administration of 100,000-200,000 lacs I.U. of vitamin A to pregnant rats between 8th-14th days of gestation. In the present study, fetuses with apparently normal external ears were examined histologically and found to have equally severe malformations of the middle ear cavity, ear ossicles, cochlear and the semicircular canals which highlights the inadequacy of mere surface examination as a method of estimation of a teratogenic effect.