One of the cardinal rules for expectant moms: don’t drink.But a new study out of Denmark is throwing that maxim into doubt. It finds that 5-year-olds whose mothers drank low to moderate levels of alcohol (between one and eight drinks a week) during early pregnancy showed no ill effects.

Alcohol consumption during pregnancy that exceeded the “moderate” threshold, however, was associated with a lower attention span among children in that age group.

Despite the findings, experts who reviewed the research said it shouldn’t change standard recommendations.

“These findings can easily send a very dangerous message to pregnant women,” said Bruce Goldman, director of Substance Abuse Services at the Zucker Hillside Hospital in Glen Oaks, N.Y. He noted that the U.S. surgeon general advises against drinking during pregnancy to avoid fetal alcohol spectrum disorders.

“Women may underestimate and have difficulty acknowledging the frequency or quantity of alcohol consumed,” Goldman said. “Those suffering from alcoholism may attempt to rationalize that it is safe to drink moderately, something they may ultimately be unable to do.”