Cervical elastography using E-cervix for prediction of preterm birth in singleton pregnancies with threatened preterm labor

Objective: E-Cervix™ (WS80A; Samsung, Seoul, Korea) elastography is a recent quantification tool to measure the stiffness of the cervix using strain elastography. The aim of this study was to evaluate the prediction performance of E-cervix for preterm birth in singleton gestation with threatened preterm labor (PTL). Methods: This was a cohort study of singleton pregnancies without prior preterm birth presenting to obstetrics triage for threatened PTL between 23 0/7 and 33 6/7 week who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-cervix at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyses raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal os (IOS) and external os (EOS). Results: Ninety-five singleton pregnancies without prior preterm birth and with threatened PTL between 23 0/7 and 33 6/7 week of gestation were included in the study. Forty-two (44.2%) had cervical length <25 mm, and were admitted for true PLT. Out of the 53 women with cervical length ≥25 mm, 40 (75.5%) were discharged, and 13 (24.5%) were admitted. Women with threatened PTL but without true PTL, had significantly higher HR compared to those with true PTL (49.0 ± 20.9% versus 34.8 ± 19.6%; p < .01), and significantly lower stiffness of cervical IOS and EOS. Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm, in overall cohort, and in the subset of only women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01). Conclusions: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL. Women with low HR, especially with HR less than 50 or 35%, are at increased risk of PTB. Condensation: Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01). Key message: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL.