I normally go for 'I'm driving' or 'I don't think its a good idea as I have been really unwell recently and advised not to drink', both of which are true so I don't think its really lying. The trouble is that people often guess and now that I'm on my 3rd pregnancy I can't be bothered with lying all the time and think it might be easier if people just knew!
What do you normally drink? couldn't you just keep helping yourself to ice and soda if its wine, you could have a teeny amount and just keep watering it down. or say you are dieting and are cutting down on alcohol, but this might mean you have to pass on dessert to make it more plausabe!
I have over-educated friends, so I looked up the name of an antibiotic which makes you sick if you drink (as opposed to one which simply doesn't work as well when you drink). Unlikely to be a problem with PIL, but at a hen do when I was 10 weeks it was bloody vital! The handy antibiotic in question is metronidazole, commonly prescribed by dentists!
Ive got a hen do coming up and ill be 9/10wk so im calling bride to be day before saying, dont worry im still coming but feel really ill, hopefully that will keep people at bay for the whole wkd, my best friend and sister will be getting me vodka and coke (without the vodka!!) but its the shots that i cant get away with so if abit unwell they mite not bother with me!!!