The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings may not have been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009. For more information, see the Explanation of Levels of Evidence for Developmental Toxicity. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
Ethylene Chlorohydrin (2-chloroethanol), a widely used industrial chemical and reaction product of the gaseous sterilant ethylene oxide, was evaluated for toxic and teratogenic effects in artificially inseminated New Zealand white rabbits which were matched for body weight across treatment groups on gestational day 0. ECH in 5% dextrose was administered daily in a volume of 0.3 ml/kg of body weight on gd 6 through 14 at dosages of 0, 9, 18 or 36 mg/kg/day, intravenous. An untreated control group was also included in the study. Females were weighed and observed daily during treatment for clinical signs of toxicity. At sacrifice on gd 30, a total of 15 to 21 dams (i.e., confirmed-pregnant females) per treatment group were evaluated. The gravid uterus of each dam was weighed and the number of implantation sites, and live, dead or resorbed fetuses were recorded. Each live fetus was weighed, sexed, and examined for external, visceral and skeletal malformations.
Administration of ECH (0, 9, 18 or 36 mg/kg/day, intravenous) on gd 6 through 14 resulted in mortality rates of 4.3% (1/23), 5.2% (1/19), 13.6% (3/22) and 15.0% (3/20) for the vehicle control through high-dose groups, respectively. No unscheduled deaths occurred among 17 untreated females. Clinical signs observed in the ECH (0, 9, 18 or 36 mg/kg/day) groups included hyperactivity, lacrimation and diarrhea, but no apparent relation to dose was observed. Measures of maternal body weight (gd 0, 6, 10, 14 and 30), maternal weight gain (i.e., weight gain during gestation, weight gain during treatment and absolute weight gain), gravid uterine weight and maternal liver weight were not found to differ statistically among treatment groups. Examination of uterine contents on gd 30 revealed no differences among groups in the percentage of resorbed, dead, nonlive (i.e., dead plus resorbed) or affected (i.e., nonlive plus malformed) fetuses per litter. Nor were average live litter size, percentage of males per litter or average fetal body weight per litter altered by ECH treatment. No evidence of a treatment-related teratogenic effect was observed, even at the highest dose.
In conclusion, no evidence was observed for a fetotoxic or teratogenic effect of ECH (0, 9, 18, or 36 mg/kg/day, intravenous) administered to NZW rabbits on gd 6 through 14.