Combination of cervical elastographic parameters and cervical length for the prediction of spontaneous preterm birth in second trimester of pregnancy / 中华超声影像学杂志

ABSTRACT

Objective:To evaluate the characteristics of cervical hardness and softness in the second trimester, and to explore the predictive value of the combination of cervical elastographic parameters and cervical length(CL) in spontaneous preterm birth (sPTB).Methods:The clinical data of 147 women with full-term birth(full-term birth group) and 24 women with sPTB(sPTB group) who received prenatal examination in Chengdu Women′s and Children′s Central Hospital from January 2018 to December 2019 were reviewed. Multiple parameters were measured between 16-28 gestational weeks by the transvaginal ultrasound E-cervix technique. CL, elasticity contrast index(ECI), hardness ratio(HR), mean strain at internal os(IOS), mean strain at external os(EOS), the ratio of IOS to EOS(IOS/EOS) were obtained.Elastographic parameters and CL were compared between the two groups. Furthmore, binary regression was established, while the area under ROC curve(AUC) was used to evaluate the predictive efficiency of elastographic parameters and CL in sPTB, both alone and in combination with other parameters.Results:The elastographic parameters IOS and IOS/EOS in the sPTB group were higher than those in the full-term birth group, while HR and CL were lower than those in the full-term birth group (all P<0.05). There were no statistical differences of ECI and EOS between the two groups(both P>0.05). The AUCs of predicting sPTB with single IOS, IOS/EOS were 0.684 and 0.625, higher than the AUCs of HR, CL. The combination of IOS/EOS and CL, IOS and CL showed higher AUCs than elastographic parameters alone, with the AUC 0.788 of IOS/EOS combined with CL. The sensitivity was 70.8%, and the specificity was 87.3% corresponding to the optimum cutoff value(IOS/EOS was 1.22, CL was 3.46 cm). Conclusions:In the second trimester, sPTB has a lower hardness cervix than that of full-term women, especially the internal os of cervix. The combination of IOS/EOS and CL tends to improve the ability of predicting sPTB in pregnant women.