Hi there, I never had any spotting after my ultra sound however i did have some spotting at the times my period was due, ie 8 weeks and 12 weeks. I went to the hospital and they did a scan and all was ok, they said that it can happen to some people. Try not to worry too much about it there could be plenty of reasons for it and if you still have spotting after a couple of days then i would go straight to the hospital, don't wait for your doctor to give you another referral etc. At least at the hospital they have the facilities to check you straight away to put your mind at ease. Hope all goes well and once again try not to stress too much about it.