interesting VBAC question

Recently someone asked me if she was a good candidate for VBAC. Her first birth, by cesarean with low transverse incision, was at thirty weeks (due to a rare infection).
Now obviously I asked her what her care provider said, since what she is asking is a medical question. He is encouraging her to VBAC but she is still concerned. I have also suggested that perhaps she should explore whether she is with the right care provider, given her concerns in spite of her provider's reassurance.

In any case, back to VBAC for someone who has had a premature birth by cesarean...
Her question was an interesting one that I had not considered before: is a low trasverse incision on a thirty week uterus the same as on a 40 week uterus, ie. is it still "low" once the uterus grows beyond the size it was when the prior cesarean was done and does this situation mean more of a risk of uterine rupture?

This woman is well-read and had done her research but had not found anything yet. I threw the question out to both an OB & a midwife with whom I work frequently. Both were in agreement that it didn't seem like an additional risk. And fortunately the OB was able to find a study on point that finds this scenario imposes a very, very minimal increased risk for uterine rupture.