Teratogenicity of triamcinolone acetonide in rats

<jats:title>Abstract</jats:title><jats:p>The objective of this investigation was to study the teratogenic effects of triamcinolone acetonide (TAC) in the rat. Pregnant females were injected intramuscularly once each day for three consecutive days (days 9–11, 12–14, or 15–17 of gestation) either with vehicle alone or with 0.125, 0.25, or 0.5 mg/kg TAC. All animals were euthanized on day 20 of gestation, and the fetuses were fixed for razor blade sectioning and skeletal examination. No maternal lethality was elicited in any of the treatment groups. There were decreases in fetal viability in the two higher dose groups treated on days 12–14 and the group treated with 0.5 mg/kg on days 15–17. These same three treatment groups showed significant increases in the percentage of malformed fetuses. The most prevalent malformation was cleft palate, with both complete and partial clefts being detected. Umbilical hernias and undescended testes were also found to be significantlymore frequent in the high‐dose group treated on days 12–14. A reduced degree of ossification was found in all TAC‐treated groups, but no specific skeletal malformations were detected. Fetal weight was significantly reduced in all TAC‐treated groups. The results demonstrate that (1) TAC affects a variety of developmental processes resulting in resorption, cleft palate, umbilical hernias, undescended testes, reduced ossification, and fetal growth retardation, (2) these teratogenic effects are elicited at doses causing no maternal lethality, and (3) fetal growth retardation can be produced at doses below those required to produce malformations and during periods of gestation where no malformations are produced, supporting the use of this parameter as a sensitive indicator of embryotoxicity.</jats:p>