External Validation of a Prediction Model for Successful External Cephalic Version

Abstract

We sought external validation of a prediction model for the probability of a successful external cephalic version (ECV). We evaluated the performance of the prediction model with calibration and discrimination. For clinical practice, we developed a score chart to calculate the probability of a successful ECV. We studied 320 women undergoing ECV, of which 117 (37%) were successful. The model underestimated the success rate by 4 to 14%. The area under the receiver operating characteristic curve was moderate (0.66; 95% confidence interval: 0.60 to 0.72), but the model was able to make good distinction between women with a higher predicted probability of a successful ECV (more than 50%) compared with women with a lower predicted probability of a successful ECV (less than 20%). Our model to predict the outcome of ECV holds in external validation. It can be used to support patient counseling and decision making for ECV in singleton term breech presentations.

Keywords

breech presentation - external cephalic version - external validation - prediction model

• References

• 1 Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR Term Breech Trial Collaborative Group Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial. Lancet 2000; 356: 1375-1383
• 2 Rietberg CC, Elferink-Stinkens PM, Brand R, van Loon AJ, Van Hemel OJ, Visser GH. Term breech presentation in The Netherlands from 1995 to 1999: mortality and morbidity in relation to the mode of delivery of 33824 infants. BJOG 2003; 110: 604-609
• 3 Sheiner E, Shoham-Vardi I, Hallak M, Hershkowitz R, Katz M, Mazor M. Placenta previa: obstetric risk factors and pregnancy outcome. J Matern Fetal Med 2001; 10: 414-419
• 4 Villar J, Valladares E, Wojdyla D , et al. WHO 2005 global survey on maternal and perinatal health research group Caesarean delivery rates and pregnancy outcomes: the 2005 WHO global survey on maternal and perinatal health in Latin America. Lancet 2006; 367: 1819-1829
• 5 Hofmeyr GJ. Interventions to help external cephalic version for breech presentation at term. Cochrane Database Syst Rev 2004; (1) CD000184
• 6 Kok M, Cnossen J, Gravendeel L, van der Post J, Opmeer B, Mol BW. Clinical factors to predict the outcome of external cephalic version: a metaanalysis. Am J Obstet Gynecol 2008; 199: 630-637 , e1–e7; discussion e1–e5
• 7 Kok M, Cnossen J, Gravendeel L, Van Der Post JA, Mol BW. Ultrasound factors to predict the outcome of external cephalic version: a meta-analysis. Ultrasound Obstet Gynecol 2009; 33: 76-84
• 8 Kok M, van der Steeg JW, van der Post JA, Mol BW. Prediction of success of external cephalic version after 36 weeks. Am J Perinatol 2011; 28: 103-110
• 9 Custers IM, Steures P, van der Steeg JW , et al. External validation of a prediction model for an ongoing pregnancy after intrauterine insemination. Fertil Steril 2007; 88: 425-431
• 10 Hadlock FP, Harrist RB, Sharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body, and femur measurements—a prospective study. Am J Obstet Gynecol 1985; 151: 333-337
• 11 Schafer JL, Graham JW. Missing data: our view of the state of the art. Psychol Methods 2002; 7: 147-177
• 12 Schafer JL. Analysis of Incomplete Multivariate Data. London: Chapman & Hall; 1997
• 13 Bleeker SE, Moll HA, Steyerberg EW , et al. External validation is necessary in prediction research: a clinical example. J Clin Epidemiol 2003; 56: 826-832
• 14 Aisenbrey GA, Catanzarite VA, Nelson C. External cephalic version: predictors of success. Obstet Gynecol 1999; 94 (5 Pt 1) 783-786
• 15 Fortunato SJ, Mercer LJ, Guzick DS. External cephalic version with tocolysis: factors associated with success. Obstet Gynecol 1988; 72: 59-62
• 16 Lau TK, Lo KW, Wan D, Rogers MS. Predictors of successful external cephalic version at term: a prospective study. Br J Obstet Gynaecol 1997; 104: 798-802
• 17 Newman RB, Peacock BS, VanDorsten JP, Hunt HH. Predicting success of external cephalic version. Am J Obstet Gynecol 1993; 169 (2 Pt 1) 245-249 ; discussion 249–250
• 18 Kok M, Cnossen J, Gravendeel L, van der Post J, Opmeer B, Mol BW. Clinical factors to predict the outcome of external cephalic version: a metaanalysis. Am J Obstet Gynecol 2008; 199: 630;e1-e7 ;discussion e1–e5
• 19 Kok M, Cnossen J, Gravendeel L, Van Der Post JA, Mol BW. Ultrasound factors to predict the outcome of external cephalic version: a meta-analysis. Ultrasound Obstet Gynecol 2009; 33: 76-84
• 20 Coppus SF, van der Veen F, Opmeer BC, Mol BW, Bossuyt PM. Evaluating prediction models in reproductive medicine. Hum Reprod 2009; 24: 1774-1778
• 21 Tan JM, Macario A, Carvalho B, Druzin ML, El-Sayed YY. Cost-effectiveness of external cephalic version for term breech presentation. BMC Pregnancy Childbirth 2010; 10: 3