Prediction of preterm delivery by combined use of simple clinical tests

To investigate the usefulness of 4 clinical tests in detecting both the major symptoms (premature uterine contractility and cervical change) and causes (intrauterine infection) of preterm delivery (PTD). These were performed simultaneously on 683 pregnant women at 26 to 28 weeks of gestation.

The following four tests were performed at study entry: 1) uterine contractility by the nipple stimulation test (NST); 2) cervical length (CL) measured by transvaginal ultrasonography; 3) measurement of granulocyte elastase in cervical secretion; and 4) measurement of oncofetal fibronectin in vaginal secretion. Pregnancy outcomes were followed up and recorded for the 683 women.

Those women with a CL <25 mm showed a significantly higher PTD rate than those with a CL > or =30 mm (13.3 vs. 2.3%). This difference was dominant in primiparous women. Those women with a CL of 25 to 29 mm formed a potentially high-risk group in which a positive NST was associated with a high incidence of PTD. In contrast, granulocyte elastase in cervical secretion had no predictive efficacy for PTD during these weeks of gestation. The oncofetal fibronectin test had a very low (0.5%) positivity rate and proved to be unsuitable for routine clinical use.

The data demonstrated the usefulness of the uterine contraction induction test by nipple stimulation (NST) and cervical length (CL) measurement by transvaginal ultrasonography. The combined evaluation of the NST, CL measurement, and fibronectin assay, when necessary, was useful for the prediction of PTD.