Vaginal Birth After Cesarean VBAC; Good idea or bad idea?

September 21, 2009

Coverage of the 2009 World Congress of Perinatal Medicine

Roberta Speyer: I am Roberta Speyer and I am reporting for OBGYN.net from the World Congress on Perinatal Medicine in Berlin, Germany. I am speaking with Professor Wolfgang Henrich and we are going to discuss VBAC, vaginal birth after cesarean, a very hotly debated topic.

I have a question for you. What about VBAC, vaginal birth after cesarean? We hear a lot of controversy; it is a good idea, it is a terrible idea, do you have an opinion on that?

Professor Wolfgang Henrich: This is a very, very, very difficult question. First thing of all if you go to the literature you can see that after a C-section, overall you have a success rate of 75 percent to have the next baby vaginally. But if you go in the sub-population and in the analysis you can see that there are different positive factors and negative factors. For instance, the positive factors, if you had already had a vaginal birth before the C-section or after the C-section a vaginal birth, then in the next pregnancy you have a high chance, about 90 percent, to deliver without complications. On the other hand, if you had a protracted labor or failure of progress as a reason for the C-section, then in the subsequent pregnancy you will have only a maximum chance of 50 percent.

So, there are other, further reasons to successful prognostic factors, for instance if you have a spontaneous onset of labor with a physiological effacement of the cervix, then also your chance is increased. On the other hand if the baby is not more than 4.0 kg, so this macrosomia baby they have a bad chance to get delivered vaginally after a C-section.

You have to look into it in detail to predict the individual chance for a successful vaginal delivery after C-section.

Again, we have another option to try to predict a little bit the risk of one major factor, uterine rupture. Uterine rupture in most cases can be a catastrophe for mother and child. The child can be hypoxemic during the uterine rupture, and the mother can lose the uterus for instance, or could come into a life threatening hemorrhage situation. What is the basic risk of the uterine rupture? If you have never been operated on before it is only one in 17,000, it is really a rare event. But if you had a C-section before, you have a risk; it seems to be about 0.2 to 0.5 up to 1.5. This is a number. I mean from 100 patients 1.5 will have a uterine rupture with a catastrophe. I don’t know if you would get on an airplane if somebody would tell you at 1.5 percent this airplane will crash.

Roberta Speyer: No, I would not go.

Professor Wolfgang Henrich: You would not go. It depends very much on your counseling in the situation with the pregnant lady. What you say, and if you pronounce this number of 1.5 uterine ruptures, most of them will say, “No, I never want to try that because it is much too dangerous”.

But we might have another option to clarify a little bit more the individual risk. This is again perhaps by ultrasound, because with experience, good equipment, and good transducers you can identify by ultrasound the myometrial layer in the area of the previous C-section. It is proven in only a few studies, but there exist some studies, which show that if you have an extremely thin layer, perhaps less than 1.5 mm, perhaps less than 1.0 mm, you will have an increasing risk of rupture in that patient.

There is still an open debate about the thinning, where is the cut off and does a scar behave the same like original tissue and so on, and what is the force you need to rupture a layer of 1.0 mm and so on. Studies showed, and my own experience showed, you are even able to detect windows of the uterine scar, a daily senses of the uterine scar. We have several cases where we look in advance before the try of vaginal birth after C-section, and we look to the lower uterine segment for 36/37 weeks. When we see a daily sense, or window, we do not recommend to go under spontaneous delivery because the risk needs to be higher than if you have a stable wall about 2.0, 3.0, or 4.0 mm.

Again, we have bad news, the increasing rate increases the rates of uterine rupture during vaginal birth after C-section; on the other hand we might have the chance with ultrasound to try to find an individual risk for this situation. You also look to the biometry of the baby. You can estimate the weight of the baby. You can look to the cervical length if you have an effacement of the cervix already. It is very important to counsel these patients individually to find the right way to deliver them.

Roberta Speyer: I think that is very interesting and very helpful. Vaginal birth after cesarean, I would sum up as saying, it has risks, it may be right for some patients, may not be right for others. If you use the tools, the ultrasound that is available you can make that determination working with the patient. They can be aware of their risks and you can also look at the end and make the decision as far as how to go.

Professor Wolfgang Henrich: Again, for this topic, the decision for the first C-section has to take into account the further family planning.

Roberta Speyer: Always, thank you so much professor.

Professor Wolfgang Henrich: Thank you.