MelanieR - i will have to try and find sources for the custom, i'll get back to you guys on that one.

There is nothing wrong with discussing the pregnancy when you need to - i.e. doctors, obs, pharmacists, rabbi's or even friends if you need support... But i think the main feeling is there is no real celebrations before the baby is born, things can unfortuantly go wrong, and so its just not really supposed to be talked about for with every person you meet!

I don't know any group that doesn't have medical care.. I know one group (lubavitch) doesn't have ultrasounds, but that is for a different reason.

SaraJane - yes, we have a whole set of laws about periods.. It is a very long and complicated area (you don't have to see a rabbi unless there is a big problem), but it would take me a long time to summarize it all. If you want to google it and then ask questions look up "family purity in judaism", you should find some basic info on it.