Trial of labor following cesarean in preterm deliveries: success rates and maternal and neonatal outcomes: a multicenter retrospective study

Trial of labor after 2 previous cesareans: a multicenter study

BACKGROUND

Trial of labor after cesarean after 2 cesarean deliveries is linked to a lower success rate of vaginal delivery and higher rates of adverse obstetrical outcomes than trial of labor after cesarean after 1 previous cesarean delivery.

OBJECTIVE

This study aimed to investigate the factors associated with failed trial of labor after cesarean among women with 2 previous cesarean deliveries.

STUDY DESIGN

This was a multicenter retrospective cohort study, which included all women with singleton pregnancies attempting trial of labor after cesarean after 2 previous cesarean deliveries between 2003 and 2021. This study compared labor, maternal, and neonatal characteristics between women with failed trial of labor after cesarean and those with successful trial of labor after cesarean. Univariate analysis was initially performed, followed by multivariable analysis (adjusted odds ratios with 95% confidence intervals).

RESULTS

The study included a total of 1181 women attempting trial of labor after cesarean after 2 previous cesarean deliveries. Among these cases, vaginal birth after cesarean was achieved in 973 women (82.4%). Women with failed trial of labor after cesarean had higher rates of maternal and neonatal morbidities. Several factors were found to be associated with failed trial of labor after cesarean, including longer interpregnancy and interdelivery intervals, lower gravidity and parity, lower rates of previous successful vaginal delivery, smoking, earlier gestational age at delivery (38.3±2.1 vs 39.5±1.3 weeks), late preterm delivery (34-37 weeks of gestation), lower cervical dilation on admission, no use of epidural, and smaller neonatal birthweight. Our multivariable model revealed that late preterm delivery (adjusted odds ratio, 3.79; 95% confidence interval, 1.37-10.47) and cervical dilation on admission for labor <3 cm (adjusted odds ratio, 2.58; 95% confidence interval, 1.47-4.54) were associated with higher odds of failed trial of labor after cesarean.

CONCLUSION

In the investigated population of women with 2 previous cesarean deliveries undergoing trial of labor after cesarean, admission at the late preterm period with a cervical dilation of <3 cm, which reflects the latent phase, may elevate the risk of failed trial of labor after cesarean and a repeated intrapartum cesarean delivery.

Trial of labor after cesarean, vaginal birth after cesarean, and the risk of uterine rupture: an expert review

The decision to pursue a trial of labor after cesarean delivery is complex and depends on patient preference, the likelihood of successful vaginal birth after cesarean delivery, assessment of the risks vs benefits of trial of labor after cesarean delivery, and available resources to support safe trial of labor after cesarean delivery at the planned birthing center. The most feared complication of trial of labor after cesarean delivery is uterine rupture, which can have catastrophic consequences, including substantial maternal and perinatal morbidity and mortality. Although the absolute risk of uterine rupture is low, several clinical, historical, obstetrical, and intrapartum factors have been associated with increased risk. It is therefore critical for clinicians managing patients during trial of labor after cesarean delivery to be aware of these risk factors to appropriately select candidates for trial of labor after cesarean delivery and maximize the safety and benefits while minimizing the risks. Caution is advised when considering labor augmentation and induction in patients with a previous cesarean delivery. With established hospital safety protocols that dictate close maternal and fetal monitoring, avoidance of prostaglandins, and careful titration of oxytocin infusion when induction agents are needed, spontaneous and induced trial of labor after cesarean delivery are safe and should be offered to most patients with 1 previous low transverse, low vertical, or unknown uterine incision after appropriate evaluation, counseling, planning, and shared decision-making. Future research should focus on clarifying true risk factors and identifying the optimal approach to intrapartum and induction management, tools for antenatal prediction, and strategies for prevention of uterine rupture during trial of labor after cesarean delivery. A better understanding will facilitate patient counseling, support efforts to improve trial of labor after cesarean delivery and vaginal birth after cesarean delivery rates, and reduce the morbidity and mortality associated with uterine rupture during trial of labor after cesarean delivery.