Predictive model for spontaneous preterm labor among pregnant women with contractions and intact amniotic membranes
Archives of Gynecology and Obstetrics, 06/14/2012
de Oliveira RVB et al. – The model presented good accuracy with correspondence between predictions and observations, and has the capacity to become a useful tool for management of pregnant women with preterm labor and intact amniotic membranes.Methods
- Authors conducted a prospective observational cohort study on 70 pregnant women at between 22 and 34 weeks of gestation.
- Transvaginal sonographic evaluation on the cervix was performed once on women who had completed a course of parenteral tocolysis.
- The sonographic parameters of cervical length measurement and presence of cervical glandular area were obtained.
- The outcome variable was occurrences of preterm delivery (<35 weeks).
- Using a univariate logistic regression model, the coefficients of each independent variable were first estimated.
- To construct the predictive model, multivariate logistic regression containing all the selected variables that might be related to preterm delivery was used as the starting point.
- Accuracy, sensitivity, specificity and predictive values were used to measure associations of predicted probabilities and to check the ability of the model to predict outcomes.
- The predictive analyses were based on logistic regression models, with calculation of odds ratios and 95 % confidence intervals.
- The incidence of preterm delivery was 32.80 % (23/70).
- After validation, the predictive model proposed showed accuracy of 87.88 %, sensitivity of 78.26 % and specificity of 93.02 %.