Ultraschall Med 2012; 33 - A703
DOI: 10.1055/s-0032-1322696

Diagnostic accuracy of quantitative elastography of the cervix in the prediction of a successful labor induction: comparison with Bishop score and ultrasound cervical length

A Fruscalzo 1, AP Londero 2, C Fröhlich 1, R Schmitz 3
  • 1Frauenklinik, Mathias-SpitalRheine, Germany (current adress: St. Franziskus Hospital, DE Münster)
  • 2Clinic of Obstetrics and Gynecology, University Hospital of Udine, Italy
  • 3Klinik und Poliklinik für Frauenheilkunde und Geburtshilfe, University ofMünster, Germany

fruscal@libero.it

Objective:

To compare diagnostic accuracy of quantitative elastography of the cervix, Bishop score (BS) and ultrasound functional cervical length (FCL) in the prediction of a successful labor induction.

Methods:

Prospective pilot study including patients undergoing labor induction with vaginal prostaglandins (Dinoprostone) between July 2010 and June 2011, without preterm membrane rupture. Bishop-score, ultrasound cervical length and cervical tissue strain (TS) were assessed before starting induction. The cervical TS was measured as naturalstrain using the TDI-Q (tissue Doppler imaging – Quantification) technique after one to two cycles of compression of the cervix were exerted along the longitudinal axis of the cervix through the vaginal probe. The diagnostic accuracy was evaluated for the prediction of the following endpoints: active labor achievement (success vs. failure and time interval >48h), vaginal delivery >36h and total amount of prostaglandins used for labor induction >12mg.

Results:

We included 77 patients with a mean gestational age of 39.7±1.5 weeks, a mean strain of 0.75±0.17, Bishop score 3.7 (±1.4) of and FCL of 28.1 (±8.5). Cervical TS significantly predicted a failure of labor induction, occurred in 4 cases, both in mono- and multivariate analysis, independently of functional cervical length. The AUC for the prediction of labor induction failure was respectively 72% (58–86%) for the functional cervical length, 81% (60–100%) for the TS and 85% (70–100%) for the multivariate model considering both examinations. Considering the other outcome measures the functional cervical length showed overall the better performance, while TS performance was in any case equal or better than bishopscore. The AUC for the multivariate model was slightly improved if considering both TS and functional cervical length: respectively 72% (57–88%) for time interval to labor >48h, 80% (66–94%) for PG usage >12mg and 70% (56–84%) for vaginal delivery after 36 hours.

Conclusions:

Quantitative cervical elastography in combination with functional cervical length could be useful in the prediction of labor induction success.

Ultrasound - tissue elastography - Tissue Doppler Imaging (TDI) - cervix uteri - labor induction - sensitivity and specificity