Hi Meg,
A friend of mine is 11 wks preg. and had twins previously so she has just been to her doctor and by listening to the heartbeat the doctor says there is only one this time. So the heartbeat can be heard that early but I guess if there was anything abnormal it might not be able to be heard.

Susan's idea of booking a u/s and cancelling it if you don't need it is a good idea. My understanding is that a scan around 18 to 20 weeks was always the normal thing to do and the introduction of the one at 12 weeks is pretty new.
anney