I think it's like everything else, smoking, drinking even, yes, drug taking during pregnancy, yeah it's really, really not advisable but there will be 1001 people out there with perfectly healthy babies that did it, and sometimes I think it would be more stressful for the mother's of these little unborn souls to give up and i think that extreme stress during pregnancy has to be the worst thing going of any of them. My wife doesn't smoke, and drank in moderation whilst she was pregnant and our babies were fine. She did have unexplained miscarriages and an ectopic pregnancy and I suppose all the vehement anti everything's will say that her having the odd glass of wine might have caused the miscarriages, but to be honest I seriously doubt it. So I think you just need to use your common sense and give up if you can, but if it's going to have you climbing the walls, then just cut down.