The effect of the anti-icing additive, ethylene-glycol-monomethyl- ether (109864) (EGME), on embryo ornithine-decarboxylase (ODC) activity during organogenesis was assessed in rats. Pregnant Sprague-Dawley-rats were treated with 0, 25, 50, or 75mg/kg EGME by gavage on gestation days 6 through 12. The animals were sacrificed on gestation days 9, 11, 13, 15, or 25 if they had not yet delivered, and ODC assays were performed on the embryos. EGME treatment had no effect on maternal weight gain during gestation, but did affect the reproductive outcome in a dose dependent manner. Dose levels of 50 and 75mg/kg EGME reduced delivery of litters by 50 and 100 percent, respectively. EGME treatment also reduced pup weight, decreased litter size, and significantly prolonged gestation. Embryonic ODC activity peaked on gestation day 11, and dose dependent effects of EGME treatment on ODC activity were only observed at that time. The administration of 75mg/kg EGME to dams on gestation day 11 decreased embryonic ODC activity by 60 percent. The authors conclude that EGME treatment in rats causes developmental toxicity in the absence of maternal toxicity. They note that the highest dose resulted in dams carrying litters to term but not delivering, and they suggest that the EGME effect may be to interfere in some way with parturition.