Calculators Estimating the Likelihood of Vaginal Birth After Cesarean: Uses and Perceptions.

Introduction: A calculator estimating likelihood of vaginal birth after cesarean (VBAC) has been promoted by the Society for Maternal-Fetal Medicine, but little is known about how it is used and perceived in practice. Cutoffs for prohibiting labor after cesarean are discouraged by the calculator's developers, but such uses may be widespread. The purpose of this study was to determine how calculators predicting VBAC are used and perceived in midwifery practices.

Methods: Certified nurse-midwives and certified midwives currently providing care for labor after cesarean were surveyed between January 17, 2019, and February 7, 2019. Quantitative and text data were collected regarding the uses and perceptions of calculators among midwives and their colleagues. We compared these findings with midwives' perceptions of their ability to accommodate patient wishes for labor after cesarean. We used descriptive content analysis to evaluate themes occurring in text responses.

Results: There were 1305 valid responses. A requirement to use calculator scores for patient counseling was reported by 527 (40.4%) of responding midwives. Over 1 in 5 midwives reported that scores were used to discourage or prohibit labor after cesarean. Almost half reported some or strong disagreement with physician colleagues regarding calculator use. Interprofessional agreement and disagreement centered on how scores are used to direct clinical care or restrict patient options. Calculator scores were used in more than twice as many midwives' practices to discourage rather than encourage labor after cesarean. Descriptive analysis of text revealed 4 themes regarding calculators: inconsistent use, information counseling, informed consent, and influence patient management or options.

Discussion: Calculators predicting likelihood of VBAC success are widely used in midwifery settings and are more often used to discourage than to encourage labor after cesarean. Midwives reported both directive and nondirective counseling based on calculator scores.