Fertility and alcohol

I am a casual drinker I usually have a glass of red wine a couple of nights during the work week and then, depending on what's going on on the weekend, I will have a few drinks.Obviosly I would stop all together the second I found out I was pregnant. I have had two chemical pregnancies so far and am wondering why. Has anyone with similar habits or more  gotten pregnant and have gone on to have a healthy baby, or does everyone give up drinking altogether for months before trying?