Effects of maternal hypervitaminosis A on perinatal rat lung histology.

Retinyl acetate (160,000 USP/day in corn oil) was administered orally to pregnant Long-Evans rats during the last third of gestation. Postnatal evaluation of this treatment was assessed by examination of histologic sections of lung taken from stillborns and from pups that survived several hours. In all sections from treated litters, expansion of lung either did not appear to have occurred, or was not uniform. Control lung sections were uniformly expanded in all cases. It appears that hypervitaminosis A during the fetal period alters normal lung maturation. These data provide additional supporting evidence that the fetal period is susceptible to teratogens.