Vaginal Delivery Following Previous C-Sections

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Professor Sabaratnam Arulkumaran: "There are a group of women who've had a previous cesarean but would like to have a vaginal birth following that, and the question is whether we should allow women who've had two previous cesarean sections to have a vaginal birth. Since Professor Paul has a lot of experience from his institution, perhaps he might be able to tell us more about it."

Professor Richard Paul: "Our experience is quite significant, it's published data. When we were doing a large volume of deliveries we necessarily had to undertake a trial of labor in women with two prior cesareans. The safety of that procedure is different than with one prior, and it is complicated by a three-fold increase in uterine rupture with its consequences but it still approximates only about 2%. This particular group will never significantly lower the section rate because it only represents about 2% of the given population. Roughly, half of those women may achieve a vaginal birth so the net lowering might be 1%, and the risk is significant. In general, we are less and less interested in trying to promote VBAC in women with two prior sections. We are currently doing VBAC or trial of labor in about 7% of our patients to 10% which is about as low as we have been in many years. It's acceptable if the woman knows the risk and if the facility can deliver the baby when an emergency arises, and my feeling is fifteen minutes should be the intervention point. If you can't do that, you're better off doing elective repeat cesarean section and not undertaking the procedure, which has some risk. So we're pretty much downplaying the use of trial of labor with two prior sections."

Professor Sabaratnam Arulkumaran: "Yes, I think that's a very important point. The institutions where we allow women to have a trial of labor and a possible vaginal delivery, we should remember that when the scar gives way it may lead to acute bradycardia. Based on the study by Professor Paul, if the bradycardia lasts more than seventeen minutes before the baby is delivered, the baby is harmed, and certainly if it has been more than thirty minutes - most of the babies die at the time of delivery or soon afterwards. So the timing is of the essence, in most of the hospitals, we encourage them to audit the decision to delivery interval especially in acute problems like abruption, cord prolapse, scar dehiscence, and prolonged bradycardia longer than ten or twelve minutes. Because if they can get their act together and deliver the baby by seventeen or eighteen minutes, then the baby might do well but if it takes longer than that, then the baby might suffer neurological damage subsequently. I would like to ask Professor Paul for some more information on prolonged bradycardia, other than the study on women who had trial of labor after a previous cesarean. Is there any other literature to suggest that prolonged bradycardia could be harmful?"

Professor Richard Paul: "We certainly see babies born following a prolonged bradycardia that are acidemic and depressed. There's not an absolute direct correlation with the bradycardic event and that outcome. Some babies no doubt develop the bradycardic event but still maintain some perfusion within their system. So you have the paradox where you may observe a prolonged bradycardia, intervene, and still have a baby that isn't terribly acidemic. Theoretically, when a baby is extruded from the uterus, it will represent total cessation of circulation between the placenta and the fetus. But even then you have a window of time in the previously unstressed baby to intervene. In our experience, in the normal baby when there's an intervention within seventeen minutes there was no evidence of permanent sequela at discharge. If those babies had had prior stress factors going on in their labor, they ended up with sequela as early as ten minutes. But in general, there's a relationship - prolonged bradycardia and the occurrence of acidemia depression is time related but not in an absolute one-on-one correlation."

Professor Sabaratnam Arulkumaran: "Thank you. That information is very useful in those patients with bradycardia without a previous cesarean section. If they have bradycardia, we tend to intervene if it is more than nine to ten minutes because we think there will be some adverse outcome for the baby. What would be advisable with regards to the intervention time in relation to the duration of bradycardia?

Professor Richard Paul: "I think if you have a bradycardic event and it's seventy beats per minute for three, four, or five minutes and you find no resolution, at that time you assume the worst case and move toward emergency delivery. You don't wait nine minutes for your decision to get the baby delivered. In most places it's going to probably take eight to ten minutes to effect operative delivery. So after four or five minutes of bradycardia you have to make your decision to move towards an operative delivery. I wouldn't advise waiting nine or ten minutes. Take your steps, if you can't resolve the problem in maybe four minutes with really a prolapsed cord, and you assume there's been a bad circumstance - get the baby delivered as quickly as you can."

Professor Sabaratnam Arulkumaran: "That's very useful information for us to know, not only with a previous cesarean section but even in other circumstances. Thank you."

Professor Richard Paul: "You're welcome."

Part 1 - "Pros and Cons of C-Section on Demand in Low Risk Patients"