Prof Dorothy Bishop, Professor of Developmental Neuropsychology, Dept of Experimental Psychology, University of Oxford, said:
“This study, like previous studies, actually found slightly lower IQ in children whose mothers drank no alcohol in pregnancy compared to those who drank moderately. However, the authors argued that this could be due to lower age and educational level among abstainers. They attempted a more sensitive analysis which looked for effects of genetic differences in alcohol metabolism on child’s IQ, and this showed mild effects on average IQ only in those who drank during pregnancy. Unfortunately, though, their category of “moderate drinking” lumped together mothers who reported drinking less than one unit per week and those who drank as much as 6 units per week, making it impossible to determine from these data if there is a safe level of drinking in pregnancy.”
More responses to the study here