Does Information Available at Delivery Improve the Accuracy of Predicting Vaginal Birth after Cesarean? Validation of the Published Models in an Independent Patient Cohort

ABSTRACT

We sought to validate a proposed vaginal birth after cesarean (VBAC) prediction model that includes variables available “at or close to delivery” and compare its accuracy to one that only uses variables available at “entry to care.” We performed a retrospective cohort study of term pregnant women with a vertex singleton gestation attempting a trial of labor (TOL) after a single prior low transverse cesarean delivery. VBAC rates, predicted using the “close to delivery” model, were partitioned into deciles. The observed VBAC rate in each partition was compared with the predicted one. The accuracy of the two models was compared using the receiver operating characteristics curve. The predicted VBAC probability was higher in patients who had VBAC compared with those who failed a TOL (median [interquartile range]: 74.9% [59.6 to 86.1] versus 48.6% [35.4 to 66.7]; p < 0.001). The correlation between the observed and predicted VBAC rates was high (r = 0.98; p < 0.001). In the subset of patients who had the complete set of variables available for the two models (n = 490), the “close to delivery” model was more accurate. We validated the proposed VBAC prediction model in an independent cohort. Incorporating information available at delivery improves its accuracy.

KEYWORDS

Vaginal birth after cesarean - trial of labor - prediction model

REFERENCES

• 1 Hamilton B E, Martin J A, Ventura S J. Births: Preliminary Data for 2007. National vital statistics reports. Vol. 57. No 12. Hyattsville, MD: National Center for Health Statistics; Released March 18, 2009. Available at: http://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_12.pdf
• 2 Martin J A, Hamilton B E, Sutton P D et al.. Births: Final Data for 2006. National Center for Health Statistics. January 7, 2009. Available at: http://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_07.pdf Accessed June 1, 2010
• 3 American College of Obstetricians and Gynecologists . Vaginal birth after previous cesarean. ACOG Practice Bulletin No. 54.  Obstet Gynecol. 2004;  104 203-212
• 4 Landon M B, Leindecker S, Spong C Y National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network et al. The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery.  Am J Obstet Gynecol. 2005;  193 (3 Pt 2) 1016-1023
• 5 Landon M B, Hauth J C, Leveno K J National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery.  N Engl J Med. 2004;  351 2581-2589
• 6 NIH Consensus Development Conference on Vaginal Birth after Cesarean: New Insights. March 8–10, 2010. Bethesda, MD; Available at: http://consensus.nih.gov/2010/images/vbac/vbac_statement.pdf Accessed May 24, 2010
• 7 Grobman W A, Lai Y, Landon M B National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU) et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery.  Obstet Gynecol. 2007;  109 806-812
• 8 Grobman W A, Lai Y, Landon M B for the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network et al. Does information available at admission for delivery improve prediction of vaginal birth after cesarean?.  Am J Perinatol. 2009;  26 693-701
• 9 Costantine M M, Fox K, Byers B D et al.. Validation of the prediction model for success of vaginal birth after cesarean delivery.  Obstet Gynecol. 2009;  114 1029-1033
• 10 Zweig M H, Campbell G. Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine.  Clin Chem. 1993;  39 561-577
• 11 Hanley J A, McNeil B J. The meaning and use of the area under a receiver operating characteristic (ROC) curve.  Radiology. 1982;  143 29-36
• 12 Lasko T A, Bhagwat J G, Zou K H, Ohno-Machado L. The use of receiver operating characteristic curves in biomedical informatics.  J Biomed Inform. 2005;  38 404-415
• 13 Lilliefors H W. On the Kolmogorov-Smirnov test for normality with mean and variance unknown.  J Am Stat Assoc. 1967;  62 399-402
• 14 Rossi A C, D'Addario V. Maternal morbidity following a trial of labor after cesarean section vs elective repeat cesarean delivery: a systematic review with metaanalysis.  Am J Obstet Gynecol. 2008;  199 224-231
• 15 Grobman W A, Lai Y, Landon M B Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network et al. Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor?.  Am J Obstet Gynecol. 2009;  200 56-e1–e6