Is it possible to improve diagnostic and prognostic criteria of preterm labour?

Preterm labour is a frequent cause of admission to hospital during pregnancy. However, in most cases, preterm labour is diagnosed with reference to clinical criteria only. Since the clinical assessment of uterine contractions and of cervical changes is highly subjective, few of the patients admitted to the hospital with suspected preterm labour will ultimately deliver preterm. There is a need for sensitive methods of detecting patients who are genuinely at high risk of preterm birth, but on the other hand, specific methods of reducing unnecessary treatments or hospital admissions are also required. Recently, a few techniques such as ultrasonographic measurement of cervical length and fetal fibronectin have been introduced into clinical practice with the aim of improving prediction of the risk of actual preterm delivery. In the future, the assessment of cervical status may be based not only on anatomical changes, but also on functional criteria. New techniques are being developed for evaluation of the mechanical properties of the cervix (cervical distensibility), noninvasive measurement of its collagen content (light-induced fluorescence of cervical collagen), or even direct assessment of the changes in cervical water content (magnetic resonance imaging). Correlations have been found between these measurements and the risk of preterm birth, but clinical studies are still needed to allow better assessment of the predictive value of these new methods in clinical practice.