Effects of gestational exposure to Tordon 202c on fetal growth and development in CD-1 mice.

The teratogenic effects of Tordon 202c, a picloram and 2,4-D combination formulation, are unknown. Pregnant CD-1 mice were exposed to Tordon 202c in the drinking water at concentrations of 0.10, 0.21, and 0.42% from d 6 to 15 of gestation. Fetal growth parameters, including body weight and crown-rump length, were reduced in a dose-dependent manner, as was placental weight. The incidence of dead fetuses/resorptions and malformed fetuses (especially cleft palate) was increased in the highest dosage group. A subtle indication of maternal toxicity was noted in the highest dosage group as evidenced by decreased water consumption and increased relative liver weight. The present study suggests that Tordon 202c is embryotoxic and teratogenic in CD-1 mice when administered during organogenesis.