Beyond Cervical Length: Association between Postcerclage Transvaginal Ultrasound Parameters and Preterm Birth

Abstract

Objective To assess the value of transvaginal ultrasound parameters after cerclage placement in estimating the risk of spontaneous preterm birth.

Study Design This is a retrospective cohort at a single tertiary care center from 2013 to 2016. Women carrying a singleton, nonanomalous fetus with cerclage in situ and at least one postcerclage transvaginal ultrasound from 16^0/7 to 25^6/7 weeks' gestation were included. In addition to abstracting maternal demographic and obstetric characteristics, two study investigators separately reviewed each of the images from the first transvaginal ultrasound after cerclage placement, masked to pregnancy outcomes. We measured the angle between the anterior uterine wall and cervical canal at the internal os and external os, closed canal length above and below the stitch, width of the anterior and posterior cervix at the level of the cerclage, and stitch distance from the cervical canal. The presence of additional ultrasound findings such as sludge and cervical funneling was also noted. The main outcomes were preterm birth < 34 weeks and preterm birth < 37 weeks. Transvaginal ultrasound parameters were compared between women with preterm birth and those without preterm birth using chi-square, Fisher's exact, and Wilcoxon's rank-sum tests, as appropriate. Log binomial regression was used to estimate the relative risk of preterm birth for all significant obstetric and ultrasound characteristics.

Results A total of 102 women met inclusion criteria: 58% had history-indicated, 20% ultrasound-indicated, and 23% exam-indicated cerclages. Of these, 28 (27.5%) women delivered at < 34 weeks' gestation, and 48 (47.0%) women delivered at < 37 weeks' gestation. Preterm birth did not vary by race, maternal age, insurance, smoking, or gestational age of the earliest prior preterm birth (for multiparous women), but women who had preterm birth were more likely to have exam-indicated cerclage. There were several transvaginal ultrasound parameters associated with preterm birth < 34 weeks and preterm birth < 37 weeks. Of these, cervical length below the stitch, stitch distance from the cervical canal, straight cervical canal, funneling to or past the stitch, and presence of sludge had the greatest effect sizes.

Conclusion Rates of preterm birth are high postcerclage. In addition to measuring cervical length, utilization of postcerclage transvaginal ultrasound to evaluate the location of the cerclage within the cervix, the curvature of the cervical canal, and the presence of funneling and sludge may help identify women who are at the highest risk for preterm birth.

Keywords

cerclage - cervical length - preterm birth - ultrasound - uterocervical angle

Note

This study was presented in poster format at the 38th annual meeting of the Society for Maternal-Fetal Medicine, Dallas, TX, January 29–February 3.

• References

• 1 Manuck TA, Rice MM, Bailit JL. , et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Preterm neonatal morbidity and mortality by gestational age: a contemporary cohort. Am J Obstet Gynecol 2016; 215 (01) 103.e1-103.e14
• 2 Committee on Practice Bulletins—Obstetrics, The American College of Obstetricians and Gynecologists. Practice bulletin no. 130: prediction and prevention of preterm birth. Obstet Gynecol 2012; 120 (04) 964-973
• 3 Gilbert WM, Nesbitt TS, Danielsen B. The cost of prematurity: quantification by gestational age and birth weight. Obstet Gynecol 2003; 102 (03) 488-492
• 4 American College of Obstetricians and Gynecologists. ACOG practice bulletin no.142: cerclage for the management of cervical insufficiency. Obstet Gynecol 2014; 123 (2 Pt 1): 372-379
• 5 Kurup M, Goldkrand JW. Cervical incompetence: elective, emergent, or urgent cerclage. Am J Obstet Gynecol 1999; 181 (02) 240-246
• 6 Berghella V, Rafael TJ, Szychowski JM, Rust OA, Owen J. Cerclage for short cervix on ultrasonography in women with singleton gestations and previous preterm birth: a meta-analysis. Obstet Gynecol 2011; 117 (03) 663-671
• 7 Suhag A, Berghella V. Cervical cerclage. Clin Obstet Gynecol 2014; 57 (03) 557-567
• 8 Cook JR, Chatfield S, Chandiramani M. , et al. Cerclage position, cervical length and preterm delivery in women undergoing ultrasound indicated cervical cerclage: a retrospective cohort study. PLoS One 2017; 12 (06) e0178072
• 9 Dziadosz M, Bennett TA, Dolin C. , et al. Uterocervical angle: a novel ultrasound screening tool to predict spontaneous preterm birth. Am J Obstet Gynecol 2016; 215 (03) 376.e1-376.e7
• 10 Knight JC, Tenbrink E, Sheng J, Patil AS. Anterior uterocervical angle measurement improves prediction of cerclage failure. J Perinatol 2017; 37 (04) 375-379
• 11 Swanson K, Grobman WA, Miller ES. Is uterocervical angle associated with gestational latency after physical exam indicated cerclage?. Am J Perinatol 2018; 35 (09) 840-843
• 12 Song RK, Cha H-H, Shin M-Y. , et al. Post-cerclage ultrasonographic cervical length can predict preterm delivery in elective cervical cerclage patients. Obstet Gynecol Sci 2016; 59 (01) 17-23
• 13 Kim RS, Gupta S, Lam-Rachlin J, Saltzman DH, Rebarber A, Fox NS. Fetal fibronectin, cervical length, and the risk of preterm birth in patients with an ultrasound or physical exam indicated cervical cerclage. J Matern Fetal Neonatal Med 2016; 29 (22) 3602-3605
• 14 Dijkstra K, Funai EF, O'Neill L, Rebarber A, Paidas MJ, Young BK. Change in cervical length after cerclage as a predictor of preterm delivery. Obstet Gynecol 2000; 96 (03) 346-350
• 15 Taghavi K, Gasparri ML, Bolla D, Surbek D. Predictors of cerclage failure in patients with singleton pregnancy undergoing prophylactic cervical cerclage. Arch Gynecol Obstet 2018; 297 (02) 347-352
• 16 Uquillas KR, Fox NS, Rebarber A, Saltzman DH, Klauser CK, Roman AS. A comparison of cervical length measurement techniques for the prediction of spontaneous preterm birth. J Matern Fetal Neonatal Med 2017; 30 (01) 50-53
• 17 Romero R, Espinoza J, Gonçalves LF, Kusanovic JP, Friel L, Hassan S. The role of inflammation and infection in preterm birth. Semin Reprod Med 2007; 25 (01) 21-39
• 18 Miller ES, Gerber SE. Association between sonographic cervical appearance and preterm delivery after a history-indicated cerclage. J Ultrasound Med 2014; 33 (12) 2181-2186