Physical anomalies and developmental delays in nonhuman primate infants exposed to weekly doses of ethanol during gestation

Ethanol was orally administered once per week to 54 gravid pigtailed macaques (Macaca nemestrina) in doses of 0.0, 0.3, 0.6, 1.2, 1.8, 2.5 or 4.1 gm/kg from the 1st week in gestation or in doses of 2.5, 3.3, or 4.1 gm/kg from the 5th week. Mean maternal mean peak plasma ethanol concentrations (MPPEC) ranged from 24 +/- 6 mg/dl at the 0.3 gm/kg dose to 549 +/- 71 mg/dl at the 4.1 gm/kg dose. Thirty-three viable infants were followed from birth to 6 months of age and assessed for growth, health, congenital anomalies and developmental rate. Facial anomalies, growth deficiency, or central nervous system dysfunction were found in 57% of the alcohol-exposed animals. No animal showed all the features of the human fetal alcohol syndrome. Ten of the twelve animals (83%) with mean MPPEC above 140 mg/dl had evidence of a teratogenic impact. The animals with full gestational exposure to ethanol and mean MPPEC between 140 and 249 mg/dl had much more severe and consistent cognitive abnormalities than the animals with delayed gestational exposures, even though the latter were exposed to mean MPPEC between 260 and 540 mg/dl. Conclusions from this study included: 1) ethanol-related behavioral teratogenesis occurred without accompanying physical anomalies, 2) measurable teratogenic effects from weekly exposures occurred only at intoxicating doses of ethanol, and 3) early gestational exposure to ethanol appeared to be more damaging to cognitive function than later and considerably greater alcohol exposure.