FWIW, here’s a Cochrane review on RCTs of such encouragement designs. It’s basically a failed meta-analysis in that the data is too spotty to make any conclusions. But it shows at the very least that such studies have been done before. An encouragement design in a population with high alcohol use seems most promising for figuring out the causal effect on fetuses, as you say.
(Another recent meta-analysis on the same question finds a slight decrease in preterm birth in the alcohol education group, but this is based on just three studies and marginally significant so I’d say it’s still uncertain.)
These seem most consistent with the effect of light drinking being small or zero, though it’s hard to be certain with the sample sizes given and the difference in study designs.
I wish someone would do a large, well-designed, well-run RCT of an encouragement design so we could have a definitive answer to this question.
FWIW, here’s a Cochrane review on RCTs of such encouragement designs. It’s basically a failed meta-analysis in that the data is too spotty to make any conclusions. But it shows at the very least that such studies have been done before. An encouragement design in a population with high alcohol use seems most promising for figuring out the causal effect on fetuses, as you say.
(Another recent meta-analysis on the same question finds a slight decrease in preterm birth in the alcohol education group, but this is based on just three studies and marginally significant so I’d say it’s still uncertain.)
These seem most consistent with the effect of light drinking being small or zero, though it’s hard to be certain with the sample sizes given and the difference in study designs.
I wish someone would do a large, well-designed, well-run RCT of an encouragement design so we could have a definitive answer to this question.