Introduction: Ethanol is teratogenic, interferes with folic acid and is extensively used by young women. Our objective was to determine the effects of ethanol and/or folate deficiency on mouse fetuses.

Method: In Experiment 1, pregnant mice receiving a commercial diet were divided into three groups: control (C), low ethanol dose (LE, 0.4 g/kg), and high ethanol dose (HE, 4.0 g/kg). In Experiment 2, pregnant mice receiving a folate-free diet (FFD) were divided into three groups: folate deficiency (FD), folate deficiency plus a low ethanol dose (FDLE), and folate deficiency plus a high ethanol dose (FDHE). Groups C and FD received saline and the remaining groups received ethanol administered i.p. from the 7th to the 9th gestational day (GD) and were sacrificed on the 18th GD.

Results: In Experiment 1, Group HE presented congenital anomalies, late fetal death (LFD), lower fetal length and weight and placental weight and diameter than Groups C and LE. In Experiment 2, there was a smaller number of live fetuses, a larger number of reabsorptions and LFD, a smaller length and lower fetal weight, placental weight and diameter in Groups FDLE and FDHE than in Group FD.

Conclusion: In animals receiving a commercial diet, a high ethanol dose is deleterious to the pregnancy, inducing congenital anomalies, intrauterine growth restriction, reduction of the placenta and increased LFD, events that did not occur with the low dose. However, with a folate free diet, a low ethanol dose is as deleterious as a high dose.