Alcohol in pregnancy was being discussed on another board I look at and it became clear that while most people were aware that 1, Government advice is don't drink any whilst pregnant and 2, the evidence suggests 1-2 units a week is safe, quite a few posters didn't know what a unit was and so were overdoing it!
I found this unit calculator tool and thought someone else might find it useful too if you decide to indulge with the odd drink:
www.drinkaware.co.uk/tips-and-tools/drink-diary/