Objective: To develop a scoring system to predict the likelihood of vaginal birth in patients undergoing a trial of labor after previous cesarean delivery using factors known at the time of hospital admission.
Methods: Trial of labor was attempted in 5022 patients who were assigned randomly to score derivation and score testing groups. Multivariate logistic regression modeling was used in the score derivation group to develop a predictive scoring system for vaginal birth. The scoring system was then applied to the testing group to evaluate its predictive ability.
Results: Five variables significantly affected the mode of birth and were incorporated into a weighted scoring system. Rates of successful vaginal birth after cesarean ranged from 49% in patients scoring 0-2 to 95% in patients scoring 8-10. Increasing score was associated linearly with increasing probability of vaginal birth after cesarean.
Conclusion: Increasing scores correlate with increasing probability of vaginal birth after cesarean. The admission vaginal birth after cesarean scoring system may be useful in counseling patients regarding the option of vaginal birth or repeat cesarean delivery. This information could be particularly valuable for the patient who opts for trial of labor but has second thoughts about her mode of birth when labor begins.