Evaluation of the Teratogenic Toxicity of Sunset Yellow in Sprague–Dawley Rats

Sunset Yellow (SY) is a synthetic azo colorant widely used in food and pharmaceutical products, resulting in increased human exposure. However, studies on its teratogenic toxicity in mammals remain limited. This study aimed to evaluate the effects of prenatal SY exposure on pregnant rats and their fetuses in Sprague–Dawley (SD) rats. Fifty successfully mated female SD rats were randomly assigned to three SY‐treated groups (40, 160, and 640 mg/kg SY, respectively), one negative control group (distilled water), and one positive control group (300 mg/kg aspirin). Gavage administration was conducted from gestational day 6 (GD 6) to GD 15 (10 consecutive days). On GD 20, the pregnant rats were euthanized for necropsy; reproductive parameters were recorded, and fetuses were collected for comprehensive developmental evaluation. The results showed that, under the present experimental conditions, SY exposure at all three doses did not adversely affect maternal clinical signs, body weight gain, or reproductive parameters, nor did it cause any deleterious effects on fetal growth, development, or visceral organs. Although a narrower fontanelle was observed at 640 mg/kg compared with the negative control group, given the absence of other developmental toxicity and the normal variation in fontanelle closure, this finding should be considered preliminary and warrants further study.