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.
Phenol, a widely used industrial chemical and antimicrobial agent, was evaluated for toxic and teratogenic effects in timed-pregnant CD-1 mice. Phenol (0, 70, 140 or 280 mg/kg/day, po) in distilled water was administered in a volume of 10 ml/kg of body weight on gestational days 6-15. Females were weighed daily during treatment and observed for clinical signs of toxicity.
A total of 22-29 females/group were confirmed to be pregnant at sacrifice on gd 17. The gravid uterus of each dam was weighed and the uterine contents examined for implantation sites and fetuses (live, dead or resorbed). Each live fetus was weighed and examined for external, visceral and skeletal malformations.
Dams in the high-dose group exhibited statistically significant signs of maternal toxicity (i.e., reduced maternal body weight and reduced weight gain), increased maternal mortality, and clinical signs including tremors and ataxia during phenol treatment.
Examination of gravid uteri at term (gd 17) revealed no significant differences among treatment groups in the incidence of resorptions, dead fetuses or malformed fetuses. Gravid uterine weight, as well as average live fetal body weight per litter was decreased in a dose-related manner, with the high-dose group significantly below controls for both measures.
Although no statistically significant evidence for a teratogenic effect of phenol in CD-1 mice was observed under the conditions of the present study, data from the preliminary investigation suggest that increased malformations (primarily cleft palate) may occur with high-dose exposure to phenol in conjunction with compromised maternal status.