Reduced birth length and weight, microcephaly, and characteristic facial deformities (smooth philtrum and thin vermillion border) are associated with alcohol exposure during the second half of the first trimester and are dose-related.  In this prospective study including 992 subjects, there was no evidence of a threshold, indicating that women should be advised to abstain from alcohol consumption from conception throughout pregnancy.

Feldman HS, Jone KL, Lindsay S, et al.  Alcohol Exposure Patterns and Alcohol-Related Birth Defects and Growth Deficiencies: A Prospective Study.  Alcohol Clin Exp Res. 2012; published online Jan 17.

Reviewed in Medscape