here and an American writer's view of the initiative here.
It's a voluntary scheme, and at the moment is just in Minnesota, but the group involved has great ideas about expansion. If it becomes more widespread in the USA, you can be sure that our anti-alcohol campaigners will begin to lobby for it in the UK. With our government's increasingly nanny-statist approach to alcohol, how certain can we be that, if it takes off voluntarily, that there isn't then pressure for it to become compulsory? This suggestion treats women like children and seems to me rather intrusive into their privacy. I wouldn't be surprised if the people behind it were mostly male, but that's just me surmising.
If it all sounds like Cloud Cuckoo Land, I never thought that legal drinkers under 21 would be required to produce ID in Britain, but in many places they are. I would have been quite annoyed when I was that age. Yes, this pregnancy test idea is unlikely to become general over here, but 'unlikely' does not mean 'impossible'.