L.B.
I agree with Sarah! I am not sure what causes scar tissue from a vaginal delivery, but your skin scars from stretching (stretch marks are scar tissue), so she may be right about it just being from stretching. Ask your doctor.
Also, many doctors will want to keep an eye on anything that is at all out of the ordinary, dangerous or not. OBs can be used for up to 21 YEARS after a child is born if anything happens, which makes them EXCEEDINGLY cautious.
THink about it -- 1/3 of all deliveries in the US happen via c-section. Every single one of those women has scar tissue on her uterus. Have you ever heard of one of them having a real problem from it? I haven't, and I used to work in L&D! Bad scar tissue makes it more complicated to do a c-section, but in every instance I observed, that just meant that the OB spent longer making the incisions. No big deal.
I agree that you need to stop reading things on the internet (I've done it myself) and talk to your doctor. Your case is unique, let him/her give you the information that is appropriate for your particular case.
Congratulations on your pregnancy!