This study explores the effects of light maternal ethanol consumption during pregnancy on the appearance of minor malformations in neonates as well as on the contractile properties of their umbilical cord arteries (UCAs). Clinical external findings of newborns of women declaring light ethanol consumption during any period of their pregnancies [ethanol-exposed group (E group), n = 79] were compared with those of nonexposed mothers [nonexposed to ethanol group (NE group), n = 100]. Women who smoked or had any associated pathology were excluded. E group mothers consumed, on average, 200-250 mL ethanol/trimester (upper limit 700 mL/trimester). Sixty-six percent of the neonates in the E group presented at least one minor malformation (retromicrognathia and minor anomalies of the auricular/preauricular area were the more common), whereas only 16% of the NE group did (p = 0.0000). The percentage of children exhibiting Apgar scores <7 was significantly greater in the E group (11% versus 2%, p = 0.0119). UCAs from the E group developed significantly less contractile force (p < 0.05) than those of the NE group when exposed to 1 μM serotonin (5-HT) or to a high K depolarizing solution. This difference persisted after inhibition of endothelial release of nitric oxide (NO) and prostacyclin. In conclusion, even light drinking should be considered a risk during pregnancy.Facultad de Ciencias ExactasFacultad de Ciencias Médicas