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.

The efficacy of quantitative fetal fibronectin in predicting spontaneous preterm birth in symptomatic women: A retrospective cohort study.

BACKGROUND: Recent data suggest that quantitative measurements of fetal fibronectin can be used accurately to predict increased risk of preterm birth. AIM: The purpose of this study was to demonstrate that the quantification of fetal fibronectin improves diagnostic accuracy in women who present with symptoms suggestive of threatened preterm labour (TPL) using a quantitative fetal fibronectin (qfFN) bedside analyser. STUDY DESIGN: This was a retrospective cohort study of pregnant women who presented between 22+6 and 32+6  weeks gestation with symptoms of TPL who had qfFN measured using the Rapid fFN Q10 system. The ability to predict spontaneous preterm birth (sPTB) within 48 h, 14 days and <34 weeks gestation at qfFN thresholds of 10, 50 and 200 ng/mL was assessed. RESULTS: The overall rate of sPTB <34 weeks was 4.1% (n = 373). For deliveries within 48 h, within 14 days and <34 weeks, a qfFN threshold of 200 ng/mL had positive predictive values of 26.7%, 42.9% and 46.7%, respectively, when compared to patients with qfFN values of 0-9 ng/mL. The corresponding relative risks were 68.5, 53.8 and 38.0, respectively CONCLUSION: Quantitative fetal fibronectin testing with thresholds of 10, 50 and 200 ng/mL allows for more accurate prediction of preterm birth in symptomatic women. This higher degree of discrimination allows for more directed interventions for high-risk patients and reduces the cost and burden of unnecessary treatment for low-risk patients.