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Published on: September 5, 2011
Serial versus Once-Only Cervical Length Screening in Twin Pregnancies
Moti Gulersen1,2, Frank Jackson3, Matthew Justin Blitz2,3
1Sidney Kimmel Medical College of Thomas Jefferson University, Department of Obstetrics and Gynecology, Pennsylvania, United States, Philadelphia.
Objective:
To assess the impact of serial versus once-only transvaginal ultrasound (TVU) cervical length (CL) screening in twin pregnancies.
Study Design:
Multicenter retrospective cohort study including twin pregnancies who underwent TVU CL screening from 160/7 to 236/7 weeks of gestation between 2017 and 2022. Twin pregnancies resulting from multifetal pregnancy reduction after 14 weeks of gestation, monochorionic monoamniotic twins, and those undergoing a history-indicated cerclage were excluded. Cases were stratified into two groups based on number of TVU CL assessments: twins who had more than one CL assessment from 160/7 to 236/7 weeks' gestation (i.e., serial CL group) versus twins who had only one CL assessment at the time of their detailed fetal anatomy ultrasound from 180/7 to 216/7 weeks' gestation (i.e., once-only CL group). Sensitivity, specificity, positive predictive value, and negative predictive value of CL screening for predicting preterm birth (PTB) at various gestational age cutoffs (<34, <32, and <28 weeks of gestation) were calculated using thresholds of both ≤25 and ≤30 mm and compared between the two groups. Statistical significance was set at p < 0.05.
Results:
Of the 1,917 patients included, 962 (50.2%) were in the serial CL group and 955 (49.8%) were in the once-only CL group. The incidence of a short CL ≤ 25 mm was significantly higher in the serial CL group compared with the once-only CL group (12.6 vs. 0.9%, p <0.001). The sensitivity of CL screening for predicting PTB, when using a threshold of ≤25 mm, was higher in the serial CL group compared with the once-only CL group for each PTB cut-off (<34 weeks: 27.9 vs. 4.2%; <32 weeks: 40.7 vs. 7.4%; <28 weeks: 47.2 vs. 11.8%, respectively).
Conclusion:
Serial TVU CL screening from 160/7 to 236/7 weeks of gestation should be considered in twin pregnancies.
Key Points:
· Serial CL screening increased the detection of a short cervix compared with once-only screening.. · Serial CL screening improved sensitivity for predicting PTB compared with once-only screening.. · Serial transvaginal CL screening from 16 to 236/7 weeks should be considered in twin pregnancies..
