Research funded by the CDC suggests that it's not as bad as we think:
[T]he results suggest that light drinking (one to four drinks a week) and even moderate imbibing (five to eight drinks) may be OK. Even occasional binge drinking (five or more drinks in a single session) didn't appear to be tied to developmental issues.
Claire Zulkey confesses:
Even before I got pregnant, I knew I would probably be a woman who drank alcohol during her pregnancy. I knew it because of the wonderfully convenient anecdotal evidence of my pregnant friends who drank the occasional glass or wine or two and who then produced healthy babies (not to mention the millions of us on the planet who made it into adulthood, successfully, despite tippling moms).
But that hasn't stopped her from second-guessing herself:
Moderation has served me well in life up to this point and I’d like to think that I have good instincts. What are instincts in a pregnancy, though? We’re told to listen to the voice inside of us that says when it’s time to relax and take it easy, when it’s time to call the doctor. But my instincts also led me to think I know my body well enough to know how to treat it when I’m pregnant which includes drinking. Which is or isn’t wrong. So should I not have listened to myself? Or listen at some times and not others? I can’t wait for this all to raise its head come labor time, when women are also advised to listen to their instincts—but only to a point.
The Dish 