There are two main concerns for mothers who are expecting to become pregnant again after a cesarean section: whether they will have a spontaneous uterine rupture and whether they will be able to deliver on their own. From a physician’s perspective, the most important concern is the length of time between the last cesarean and the second pregnancy, as this is the most important factor in determining whether spontaneous uterine rupture will occur during pregnancy and whether one can safely go into vaginal delivery. The United States has accumulated more information and data in this regard, so most of the literature and the most authoritative clinical guidelines still come from the United States. In the past few years, our counterparts in China have started to pay more attention to this matter and some hospitals have started to try to allow vaginal deliveries for pregnant women who had a previous cesarean. Because less has been done, there will be a lot of confusion and different opinions. In order to solve everyone’s confusion, we will answer the questions and concerns together as follows. TOLAC (Trial Of Labor AfterC section): Vaginal birth after C-section VBAC (Vaginal Birth After C section): Vaginal birth after C-section Although TOLAC and VBAC refer to the same thing, there is still a difference. However, most people in China still use VBAC to refer to this event in general. Lower uterine incision thickness: This refers to the thickness of the muscular layer of the lower uterine incision measured by ultrasound. Some experts believe that this thickness is related to the rupture of the lower uterine segment during a vaginal trial of labor, and that the thinner the lower uterine incision thickness, the greater the risk of uterine rupture during the trial of labor. However, most experts believe that there is no universally acceptable cut-off value to predict uterine rupture, and that the values obtained vary widely depending on the method of measurement. My own attitude is not to recommend, not to oppose, and if it is to be measured, the cut-off value can be set at 3 mm. Interpretation of the US VBAC guidelines According to the literature, the success rate of VBAC is generally 60-80%, and the rate of uterine rupture in pregnant women with a history of cesarean delivery during vaginal trial of labor is 0.7-0.9%. The probability of uterine rupture is related to the length of time between pregnancies, with a 2.7% probability of uterine rupture if a VBAC is attempted within 6 months of the two pregnancies (time between cesarean delivery and second pregnancy) and a 0.9% probability of uterine rupture if a VBAC is attempted more than 6 months later. Most doctors in China would say 18-24 months is the best time to consider a VBAC after a cesarean section, which is actually a misinterpretation. If you read the original English literature carefully, you will find that the 18-24 months refers to the Interpregnancy Interval, not the Interpregnancy Interval, but to the Interpregnancy Interval minus 9 months. The Interpregnancy Interval is determined by subtracting 9 months of pregnancy from the Interpregnancy Interval, which means that anyone who becomes pregnant between 9 and 15 months after a cesarean section is eligible for VBAC. Of course, for women who are not in a hurry to get pregnant again, waiting 18-24 months is not a problem. However, women who are older and want to get pregnant again sooner, as well as women who are already pregnant again, should be allowed to consider VBAC if they are pregnant 9-15 months after cesarean delivery. I won’t go into the indications and contraindications for VBAC, which your doctor will discuss with you during your clinic visit. The data on the time between cesarean delivery and second pregnancy and spontaneous uterine rupture are relatively scarce. Data from the ACOG (American College of Obstetricians and Gynecologists) guidelines suggest a 0.4-0.5% incidence of uterine rupture in pregnant women who are scheduled for elective repeat cesarean delivery, with no indication of the time between the last cesarean delivery and second pregnancy. So even if you get pregnant again within a few months after a cesarean, it’s not that scary, the probability of spontaneous uterine rupture exists, but it’s not as high as you might think. It just means that if you want to deliver vaginally on your own, the probability of uterine rupture is three times higher, at around 3%. If you don’t want to deliver yourself and choose to have another cesarean, the probability of spontaneous uterine rupture is probably no more than 1%. Can I have a VBAC after two consecutive cesarean deliveries? Most people would say no, but it is possible. In a large sample of studies, the success rate of VBAC for those with a history of two lower uterine cesarean sections was 71% and the rate of uterine rupture was 1.36% compared to one lower uterine cesarean section. Overall the success rate is acceptable and the risks are manageable. Vaginal trial of labor can be considered with adequate information about the risks and informed consent. The incomplete VBAC data of our ICH, we are relatively early to carry out TOLAC/VBAC in ICH, we started to try VBAC around 2009, and then summed up the experience and lessons learned and formulated VBAC guidelines in 2011, then in 2012, we systematically trained and carried out VBAC in the whole hospital, and set up a special VBAC clinic. So far, more than 400 patients have successfully completed VBAC, with a success rate of more than 90% and an initial success rate of more than 95%, with one case of uterine rupture and a safe mother and baby.