Cleft palate development in hamster embryos following triamcinolone treatment.

Development of the palate was studied in normal and triamcionolone-treated hamster fetuses. The results demonstrated that normal palatogenesis was completed between days 12 and 13 of gestation. Following triamcinolone treatment the reorientation of the palatal shelves was delayed before there was any general retardation of fetal growth (as indicated by crown-rump length and body weight). Since triamcinolone affected palatogenesis at an earlier stage than hydrocortisone, the view that the former is a more potent teratogen was supported. Chronological age, fetal weight and crown-rump length were reliable predictors of normal palatogenesis in the hamster, whereas the numerical morphological rating systems were not. Neither measures of general fetal growth, nor numerical rating, were useful in predicting the stages of experimentally induced cleft palate, since triamcinolone appears to be site-specific, and the drug does not produce a general retardation of embryonic development.