Ethnic disparities in repeat caesarean rates at Auckland Hospital

Validation of updated antenatal vaginal birth after caesarean section prediction model without race and ethnicity in Australia

BACKGROUND

The Grobman antenatal nomogram to predict likelihood of successful vaginal birth after caesarean section (VBAC) has been validated in multiple institutions. However, due to concerns regarding inclusion of ethnicity, a new nomogram has been developed.

AIM

The aim was to evaluate the efficacy of the updated Grobman nomogram without ethnicity in a regional hospital in Australia.

MATERIALS AND METHODS

This was a retrospective cohort study of women electing to have a VBAC at a regional hospital over a nine-year period. Maternal demographics and obstetric outcomes were collected. Women were assigned a predicted likelihood of successful VBAC using the updated Grobman nomogram, with variables such as age, pre-pregnancy weight, height and arrest disorder as indications for previous caesarean birth, previous vaginal birth, previous VBAC and treated chronic hypertension. The predicted likelihood of successful VBAC was compared with actual successful VBAC rates.

RESULTS

A total of 541 women attempted VBAC with a VBAC success rate of 74.3% (402/541). The nomogram demonstrated good fit, with a receiver operating curve area under the curve of 0.707 (95% confidence interval 0.659-0.755). Using a cut-off value of 0.5, the success rate of classification with this model was 74.3%. On comparing each predicted decile, the nomogram performed poorly in those predicted to have a <40% chance of successful VBAC.

CONCLUSIONS

This study confirms the use of the updated Grobman nomogram without ethnicity, alongside usual counselling, to provide individualised advice for informed decision-making. However, clinicians should be mindful of the limitation of poor accuracy in women with a low predicted probability of VBAC.

Women's preference for vaginal birth after a first delivery by cesarean

BACKGROUND

Nearly 90% of United States pregnant women with a prior cesarean give birth by repeat cesarean. Public health goals encourage greater use of vaginal birth after cesarean (VBAC), but there is little prospective data on predictors of women's preference for VBAC. We characterized predictors of women's preferred mode of delivery after a first cesarean and thematically categorized reasons for their preference.

METHODS

Data were from a cohort of 3006 women whose first childbirth was in Pennsylvania in 2009-2011. The analytic sample included women who had their first birth by cesarean and reported mode of delivery preference for their next delivery at 12 months postpartum (n = 616). Associations with future birth mode preference were assessed using multivariate logistic regression, and reasons for preference were categorized using content analysis.

RESULTS

At 12 months postpartum, 45% of women who delivered by cesarean in their first birth wanted to have their next delivery vaginally. Independent predictors of VBAC preference were Black race/ethnicity, nonrecurrent indication for the first cesarean, planning three or more additional children, and difficulty recovering from the first cesarean. The most common reason for preferring a vaginal birth was wanting the experience of vaginal birth; the most common reason for preferring cesarean birth was that the first birth was by cesarean.

CONCLUSION

Nearly half of respondents preferred VBAC in future births, but national estimates indicate that only about 12% of women with prior cesareans have a VBAC. This suggests a need to ensure greater access to VBAC for women who want it.