Risk score for failed trial of vaginal birth after a previous cesarean section including data of labor course.

AIM: There is much discussion about the advantages and disadvantages of a trial of labor after cesarean (TOLAC). Some data suggest the greater the likelihood of success, the lower the risks of TOLAC. Our goal was to identify clinical and demographic variables associated with a failed TOLAC, available at admission for spontaneous labor and until 3 h later, with the aim of building two scores for risk of failed TOLAC.

METHODS

This is a nested case-control study with live births to women with one previous cesarean, in a public Brazilian teaching hospital. Preterm, induction, noncephalic presentations, twins, fetal malformations were excluded. Cases were failed TOLAC, and controls, the successful TOLAC. It was accessed the association of the cases with 20 variables (P < 0.05). Associated variables were tested in multivariate analysis to build the scores, which were internally validated.

RESULTS

We included 260 TOLAC, 42 cases and 218 controls. We found 11 variables associated with failed TOLAC. In the score to be applied at admission, we included hypertension, fundal height, previous vaginal birth and dilatation at admission. In the second score hypertension, fundal height at admission, membrane status and difference in dilatation 3 h after admission. Both scores presented good performance in the receiver-operator curve (areas under curve: 0.73 and 0.84, respectively). Both scores were translated into nomograms for clinical use.

CONCLUSION

Two scores were built for risk of failed TOLAC, to be applied at admission and 3 h later. We believe that choosing the more favorable cases makes risks of TOLAC lower.