I am not sure of the exact measurement, I didn't know enough about it at the time to ask! I have my ultrasound picture from last week when I was 6 1/2 weeks pregnant, I am not able to upload it because I haven't had 10 posts yet, I will post it later. The fibroid is a little bigger than one of the babies in the picture, and that is still small, because the babies are still tiny at this point in the pregnancy.