Accuracy of salivary estriol testing compared to traditional risk factor assessment in predicting preterm birth.

Abstract

The objective was to compare the predictive accuracy (percentage of correct vs incorrect predictions) of salivary estriol levels (SalEst; Biex, Inc, Dublin, Calif) with that of the modified Creasy score for predicting preterm labor followed by preterm delivery. A triple-blinded prospective trial was conducted at 8 US centers. Among 601 evaluable patients, serial salivary estriol testing correctly predicted the appropriate outcome 91% of the time and the Creasy scoring method correctly predicted the appropriate outcome 75% of the time (McNemar test P <. 001). Among subjects with Creasy scores >/=10 (high-risk group, n = 152), use of salivary estriol testing correctly predicted the end point 87% of the time, compared with only 7.2% correctly predicted by modified Creasy scoring (McNemar test P <.001). Salivary estriol assessment was more accurate in predicting outcome than was modified Creasy scoring.