Ooh cannot remember tbh, think around 4cm, I go annually for a scan and it was only after the 2nd scan so 2 yrs, on Utro...they dont seem to stress if it gets smaller or stays the same, just musnt get any bigger, I would use the Utro vaginally see how it goes and hear what your gynae thinks but they usually opt for watchful waiting if it appears simple on the scan....