Of course the main risk everyone hears about is the risk of uterine rupture. This is what most doctors bring attention to, unfortunately sometimes too much. Yes, this is a real and serious risk but as I have said before the risk is less than 1%. Since I want us all to be informed this is an important topic to discuss.
So what is uterine rupture anyways? There are different degrees of rupture. The least likely is a complete rupture. A complete uterine rupture is a tear through the full thickness of the uterine wall, usually at the sight of the previous c-section scar. A minor rupture is also known as a dehiscence or window. This is when the opening is very small or does not go through all the layers of the uterus.
If this occurs it is serious and potentially, though rarely, life threatening to the mother or the baby and needs to be taken care of right away. The rupture can take place during labor or even before. A rupture can also happen in women who have never had a previous c-section.
Usually there are warning signs before a rupture occurs but not always. Some warning signs include: vaginal bleeding; sharp pain between contractions; contractions that slow down, become less intense, or stop; abdominal or uterine pain; bulging under the pubic bone; sharp pain at sight of scar; low blood pressure; fetal distress; fundus may feel "boggy" or seem to be expanding; the baby can be clearly felt in the abdomen; woman in shock; extreme maternal heart beat.
Some of these warning signs occur anyways during birth but it is something to pay attention to and to be aware of. Also women might experience some, all, or none of these warning signs.
Though rare it can be serious and cause minor to major complications. When medical response is quick usually mother and baby do well. It is wise to have surgery available within 30 min for the best outcomes. In minor dehiscences there is usually no risk to the mother or the baby. For ruptures, they can happen in the lower segment of the uterus, the upper segment or where the two join. A rupture in the upper segment is the rarest but also the most serious because the baby could leave the uterus and move into the abdominal cavity and it has the most blood supply so the mother would lose the most blood and the baby would be deprived of oxygen. More likely the rupture would be in the lower segment where the baby still stays in the uterus and the mother loses less blood. Both of these would require an emergency c-section.
Fortunately if a rupture occurs mother and baby are usually fine. If a rupture occurs with excessive bleeding a clamp of an artery is needed and in some serious cases the woman might need a hysterectomy. In extreme cases when the bleeding can't be stopped a woman can go into cardiac arrest and death can occur. For the baby due to loss of oxygen brain damage can occur along with the rare risk of death.
Remember there are risks in any birth, c-section or vaginal. Although rare, death and serious complications can also happen during any birth. I found a website that put it all in perspective for me. The website is http://www.birthrites.org/uterinerupt.html. Here are some statistics from that site.
Risk of mother dying due to uterine rupture during VBAC---.0095%
Risk of mother dying in any vaginal birth---.0098%
Risk of mother dying during c-section---.0409%
Risk of mother dying during repeat c-section---.0184%
Risk of baby dying due to rupture during VBAC---.095%
Risk of baby dying during any VBAC---.2%
Risk of baby dying during any type of birth---.12%
So as you can see the likelihood of a fatal outcome of a uterine rupture is no higher than in any normal birth and actually a lot less than in c-sections. This is important to realize in case your doctor or anyone else stresses on the risks of uterine rupture in VBACs.
***Most of this info was taken from http://www.birthrites.org/uterinerupt.html