Development disability, intrauterine growth retardation, renal anomali
es, and dysmorphic features have been described in offspring of women
who abuse toluene during pregnancy. A Sprague-Dawley rat model was dev
eloped to study this clinical syndrome. During d 6-19 of gestation, 11
treated dams received daily gavage doses of toluene, 520 mg/kg body w
eight, diluted in corn oil, and 11 control dams received corn oil. Thi
s dose of toluene simulates the blood toluene levels obtained after an
inhalation exposure to 3290 ppm toluene, an inhalation level in the l
ower end of the range experienced by toluene abusers. Maternal weight
gain was 24% less in the toluene-exposed group (p < 0.002); however, t
here were no maternal deaths. The fetuses were delivered on d 19 of ge
station, and 287 fetuses (148 toluene exposed, 139 control) were exami
ned. Toluene treatment did not affect the number of implantations or s
tillbirths. There were no toluene-induced major congenital malformatio
ns or neuropathologic changes noted. In the toluene-treated group, the
weights of the fetuses were reduced by 9.4% (p < 0.004) and placental
weights were reduced by 10.3% (p < 0.01). Toluene exposure also reduc
ed fetal organ weights as follows: brain 4.6%, heart 5.9%, liver 13.2%
(p < 0.02), and kidney 13% (p < 0.05). Organ weight/body weight ratio
s did not differ significantly, suggesting that prenatal toluene expos
ure produced a generalized growth retardation.