I'll be honest, I have a 21 year old daughter who had some developmental delays. Every day of her life I have tried to blame myself in one way or another for those delays. Did the drinks I had before I knew I was pregnant contribute to them? There will never be an answer for me so I'll always live with those questions -- and it is emotional torture.
I just prefer not to live like that should this baby have any challenges, so I choose to abstain from alcohol completely. Nine months without is nothing compared to a lifetime of guilt. That said, I don't expect that everyone would do this to herself. But 21 years of experience has shown me that I would never get past it.