As the other girls have said - ooops and alan- mainly 12 and 18-20weeks are "routine". Any earlier is usually for dating and any after can be for all sorts of reasons. Bleeding, previous m/c, previous pg problems etc...

I have also had a 30 week one to check on bubs size, due to DS being small when he was born and also because of meds i am on for arthritis(can slow down growth weight towards the end of pg). I am due to have another one next week (33weeks) to check his size and possibly position (currenlty breech) and hopefully that will be all.