When we first started TTC, I tried not to drink at all. But, as the months went on with no BFP- I decided not to deprive myself when we have no idea if/when it will ever happen.
We finally started to get BFPs (we're pretty good at that part), and I was drinking pretty regularly (mostly just weekends, a glass or two during the week)... we're pretty sure it was low progesterone causing my early losses, and doctor said it couldn't have been anything I was doing that early on. I've always just stopped as soon as I got a BFP!
(had a friend that didn't know she was pregnant until 6+ weeks, and was nervous because she had a crazy night 2 days before going to the doctor- she was told it was still to early to cause damage)