Value of serial cervical length measurement in prediction of spontaneous preterm birth in post-conization pregnancy without short mid-trimester cervix

Liang Wang

doi:10.1038/s41598-018-33537-1

Abstract

Serial cervical length (CL) measurement in mid-trimester is recommended in post-conization pregnancy to estimate the risk of spontaneous preterm birth (SPTB). A short mid-trimester cervix (CL < 25 mm) has been considered as a strong predictor for SPTB. However, the low incidence of short cervix limits the utility of mid-trimester CL measurement in prediction of SPTB. A great proportion of women who develop SPTB don’t have a short mid-trimester cervix. Therefore, this study was aimed to investigate the additional value of serial CL measurement in predicting SPTB in addition to detecting short cervix alone. A total of 613 post-conization pregnant women who did not have short mid-trimester cervix between January 2004 and January 2014 were included in this study. Serial CL measurements were taken by transvaginal ultrasound at three timepoints (A: 13 + 0–15 + 6 weeks, B: 16 + 0–18 + 6 weeks, and C: 20 + 0–22 + 6 weeks). Eight parameters were analyzed for predicting SPTB, including CL measurements at different timepoints (CLA, CLB, CLC), the maximum and minimum CL measurements (CLMAX, CLMIN), and the percentage change in CL measurement between different timepoints (%ΔCLAB, %ΔCLBC, %ΔCLAC). After univariate and multivariate analysis, CLMAX and %ΔCLAC were independent variables in predicting SPTB. Lower CLMAX (OR [95%CI]: 0.92 [0.90–0.93]) and higher %ΔCLAC (OR [95%CI]: 1.05 [1.01–1.09]) were related to an increasing risk of SPTB. In conclusion, our study for the first time in literature reported the value of serial CL measurement in prediction of SPTB in post-conization pregnancy without short mid-trimester cervix. In the subpopulation of pregnant women who did not have short mid-trimester cervix, CLMAX and %ΔCLAC were of value in predicting SPTB, which warranted further investigations.

Highlights

Conization is a cone biopsy of the uterine cervix that serve as a diagnostic and therapeutic procedure, which is used for conservative treatment of cervical intraepithelial neoplasia (CIN)[1]
In the subpopulation of pregnant women who did not have short mid-trimester cervix, the predictability of spontaneous preterm birth (SPTB) was of great clinical value, only limited studies focused on this issue in previous literatures
A total of eight parameters were taken as the candidates for SPTB predictors, including cervical length (CL) measurements at different timepoints (CLA, CLB, CLC), the maximum and minimum CL measurements (CLMAX, CLMIN), and the percentage change in CL measurement between different timepoints (%ΔCLAB, %ΔCLBC, %ΔCLAC)

Summary

Introduction

Conization is a cone biopsy of the uterine cervix that serve as a diagnostic and therapeutic procedure, which is used for conservative treatment of cervical intraepithelial neoplasia (CIN)[1] This local cervical treatment has been correlated to an increased risk of spontaneous preterm birth (SPTB) in a subsequent pregnancy[2]. The low incidence of short cervix limits the utility of mid-trimester cervical screening in prediction of SPTB. Little was known about the additional value of mid-trimester cervical screening in prediction of SPTB in addition to detecting short cervix alone. In the subpopulation of pregnant women who did not have short mid-trimester cervix, the predictability of SPTB was of great clinical value, only limited studies focused on this issue in previous literatures. The present study was designed to investigate the value of serial CL measurement in prediction of SPTB in post-conization pregnancy without short mid-trimester cervix

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Conclusion