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Predictors of successful external cephalic version at term: a prospective study
Author(s) -
Lau T. K.,
Lo Keith W. K.,
Wan D.,
Rogers Michael S.
Publication year - 1997
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1997.tb12023.x
Subject(s) - external cephalic version , medicine , logistic regression , observational study , univariate analysis , population , regression analysis , prospective cohort study , subgroup analysis , univariate , palpation , obstetrics , pregnancy , surgery , statistics , multivariate analysis , meta analysis , mathematics , multivariate statistics , breech presentation , genetics , environmental health , biology
Objective To investigate clinical and ultrasonographic predictors of outcome of external cephalic version at term. Design Prospective observational study. Setting University obstetric unit. Population All external cephalic versions performed over two years ( n =243). Methods Nineteen different clinical and ultrasonographic variables were recorded before each procedure. The ability of each of the 19 variables to predict the success or failure of external cephalic version was assessed by univariate analysis. The study population was then divided into two subgroups of 129 and 114 patients by random allocation using computer generated numbers. Logistic regression was performed in each subgroup to assess the relative importance and independence of the important variables. The derived regression models were then applied to the other subgroup of patients to assess accuracy and reproducibility. Results The overall success rate of the procedure was 69.5%. Both regression models identified the same three variables as independent predictors of failed versions: 1. presenting part engaged; 2. difficult to palpate the fetal head, and 3. a tense uterus on palpation. The two models correctly predicted 75.2% and 84.2% of outcomes in the other subgroup. If uterine tone, which was assessed after administration of tocolytic, was excluded from the analysis, the other two factors remained in the models, with the addition of nulliparity as a significant predictor of failed external cephalic version. The chance of success of external cephalic version in the original 243 women was found to be < 20% if two of these variables were present, 0% if all three were present, and 94% if none were present. Conclusions The outcome of external cephalic version can be predicted by easily available clinical parameters.