Is cervical length evaluated by transvaginal ultrasonography helpful in detecting true preterm labor?

To investigate whether sonographic cervical markers can identify women in true preterm labor and predict delivery within 7 d and before 34 or 37 gestational weeks. This was a prospective observational study of women with singleton pregnancies and intact membranes given a diagnosis of preterm labor between 25 and 34 weeks and 6 d of gestation and who underwent transvaginal evaluation of the following characteristics: cervical length (CL), CL zeta score, absence of endocervical glandular echo, presence of cervical funneling, and presence of amniotic fluid sludge. The outcomes of interest were spontaneous delivery within 7 d of preterm labor and spontaneous delivery before 34 or 37 gestational weeks.