The deleterious effects exerted by prenatal ethanol exposure include physical, mental, behavioural and/or learning disabilities that are included in the term fetal alcohol spectrum disorder (FASD). Objective assessment of exposure to ethanol at both prenatal and postnatal stages is essential for early prevention and intervention. Since pregnant women tend to underreport alcohol drinking by questionnaires, a number of biological markers have been proposed and evaluated for their capability to highlight gestational drinking behaviour.