I had planned on not having any u/s at all, but now that I am pregnant I am reconsidering. If I do decide to have u/s I will only have one at 18-20wks. I don't really see a lot of point in me having one cause I've already said no to all the other tests they have offered and DH and I are not going to consider termination anyhow. I think it is definately a personal choice, however there is quite a lot of evidence to suggest u/s is less than beneficial for an unborn baby, as somebody previously mentioned unborn babes tend to really shy away from u/s. Goodluck in making your decision.