if you drink while pregnant will you miscarriage?

No, billions of women have disproved that.

Occasional moderate alcohol intake is fine, just use common sense and don't drink enough to get even slightly drunk. If an occasional drink helps to relax a pregnant woman then lower stress is of benefit to mother and foetus.

yes, you should be in jail as you just killed someone. (btw your mother probably was an alcoholic)

The reason is common sense. Your blood is the baby's blood while you're pregnant. If alcohol is in your blood it will also be in the baby's blood. Since the fetus is very small an amount of alcohol that has no affect on you will be poisonous or even fatal to the unborn child. Make sense?