So I've been watching this thread on MDC, which has since been deleted. It's about a woman who is currently 40 weeks pregnant and has had 4 previous cesareans and now has her OBs all up in arms and is currently planning an unassisted birth. Interesting read.
Note: don't read the thread unless you have an hour or two - the last time I checked it was at post #665 and no baby yet.
Second note: no mom, I'm not planning an unassisted birth. Not my cup of tea.
Update: So, I'm hooked. I need to do things like, say, clean my house, but oh no, I'm sitting here reading MDC. I found another thread about the same mom/birth/OBs here, and according to one poster (not the original poster), the original poster had a T incision with at least one of her cesareans. However, that was pointed out on page 6 right when name calling started and the thread got shut down, so I don't know for sure if it's just someone with their info messed up or for real. So I found some other threads (yes, you'll need a whole day to read all this!)
Her decision to not have a repeat cesarean
A bit about what her OB/midwife said about her scar tissue
AHA! I FOUND IT!
So yeah, that makes things more interesting. Risks of VBACs are higher with a vertical incision as opposed to a transverse incision. I don't have the actual numbers in front of me, but if you google something like VBAC transverse incision rate you'll probably find the transverse rates and likewise - just substitute vertical to get the vertical incision rates. Maybe if I get motivated later I'll look them up :)
Update #2: From Anne Frey's Holistic Midwifery:
As far as the type of incision goes, the mother who has a low transverse uterine incision is at the lowest risk for scar-related problems such as dehiscence and rupture. Those with classical or T-shaped incisions are at more risk for rupture, which tends to be more traumatic than the usually benign scar disruptions which occur in women with low transverse incisions. While some types of incisions pose more risk, the highest risk is still probably around 5% (some scars are more rare and limited data is available. From looking at the existing data, 5% seems to me a generous estimate of risk for all types of Cesarean scars, with the order of risk as follows: low transverse [0.5% Haq, 1988; to 2% Clark, 1988], low vertical [1.3% Enkin, 1989], classical and inverted T [probably about the same for both: 2.2% to 4%, depending on the study], upright T and J-incision [probably somewhat higher, but no specific data is available].). Women with an upright T, J-shaped, or classical incision or those who have experienced previous uterine rupture may want to birth in the hospital, although finding a practitioner that will assist them to have a VBAC will be more difficult.