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Transvaginal Sonographic Assessment Following Cervical Pessary Placement for Preterm Birth Prevention
Background Transvaginal sonographic cervical length assessment identifies pregnant women at risk for preterm birth, and the subsequent placement of a cervical pessary may reduce this risk. The mechanism of action remains uncertain, and postplacement transvaginal sonography may provide further insight into the controversial efficacy of this therapy.
Objective To identify any pre- or postplacement sonographic findings associated with preterm delivery following cervical pessary insertion among at-risk women.
Materials and Methods This retrospective cohort study utilized electronic medical record and imaging review of all women identified within a large tertiary care health system having undergone cervical pessary placement for preterm birth risk reduction and subsequently delivered between January 2013 (the adoption of this therapeutic option in our system) and March 2017. Indications for cervical pessary placement were guided by maternal–fetal medicine consultation and required a functional cervical length measurement on transvaginal sonography of 25 mm or less. Criteria for initial transvaginal cervical assessment included obstetric history, multiple gestation, and current concern on transabdominal imaging for cervical shortening. All pre- and postplacement transvaginal sonographic measurements were determined for study purposes by re-review of each patient's images by a single author blinded to outcome.
Results A total of 88 women were identified as having undergone cervical pessary placement for preterm birth prevention, and 52 yielded complete delivery and imaging data for inclusion. As expected, this was a high-risk population with 51.9% carrying multiple gestations, 32.7% with a history of prior preterm birth, and 11.6% with a history of cervical conization. Although previously hypothesized to represent the mechanism of action, neither the change in uterocervical or intracervical angle was associated with gestational age at delivery. Alternatively, preplacement imaging measurements of cervical funneling, anterior cervical length, and cervical diameter were significantly associated with appropriate pessary placement and decreased preterm birth. Forty-two subjects (80.8%) demonstrated both the anterior and posterior aspects of the cervix within the pessary (appropriate placement) and 95.2% of these subjects demonstrated cervical funneling on initial imaging compared with 25% of those with inappropriate placement (p = 0.002). Anterior cervical length less than 20 mm and cervical diameter less than 33 mm were associated with preterm delivery less than 28 weeks (16.7 vs. 0%, p = 0.039), and anterior cervical length less than 20 mm was associated with preterm delivery less than 32 weeks (41.7 vs. 10.7%, p = 0.025). Cervical diameter less than 33 mm correlated with an “inappropriately placed” pessary among 83.3% in comparison to 48.7% (p = 0.048) of women with a cervical diameter less than 33 mm. Significant associations were noted between postplacement functional cervical length measurements and preplacement anterior cervical length (p = 0.001) and cervical diameter (p = 0.012).
Conclusion Contrary to current thinking, no significant changes in uterocervical and intracervical angle following cervical pessary placement were identified. However, preplacement sonographic measurement of funneling, anterior cervical length, and cervical diameter are predictive of appropriate pessary placement and extreme preterm birth. These may represent markers for candidacy of cervical pessary placement. Postplacement transvaginal sonography represents an important tool to assess potential efficacy of this therapeutic modality, and further investigation of these factors is warranted.
Keywordspreterm birth - cervical pessary - uterocervical angle - intracervical angle - cervical length - funneling - sonography - ultrasound
Pre- and postpessary placement sonographic characteristics can identify ideal candidates for pessary benefit and those at risk for extreme preterm birth.
W.S. helped in conceptualization, writing—original draft, review, and editing, methodology, investigation, visualization, and supervision. K.S. helped in formal analysis, resources, and methodology. S.M. helped in conceptualization, writing—original draft, and investigation.
Received: 09 July 2020
Accepted: 08 October 2021
Article published online:
04 February 2022
© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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- 1 Committee on Understanding Premature Birth and Assuring Healthy Outcomes, Board on Health Sciences Policy. Preterm birth causes, consequences, and prevention. In: Berhman RE, Butler AS. eds. Institute of Medicine of the National Academies. Washington DC: The National Academies Press; 2007
- 2 Iams JD, Goldenberg RL, Meis PJ. et al; National Institute of Child Health and Human Development Maternal-Fetal Medicine Unit Network. The length of the cervix and the risk of spontaneous premature delivery. N Engl J Med 1996; 334 (09) 567-572
- 3 Owen J, Yost N, Berghella V. et al; National Institute of Child Health and Human Development, Maternal-Fetal Medicine Units Network. Mid-trimester endovaginal sonography in women at high risk for spontaneous preterm birth. JAMA 2001; 286 (11) 1340-1348
- 4 Berghella V, Tolosa JE, Kuhlman K, Weiner S, Bolognese RJ, Wapner RJ. Cervical ultrasonography compared with manual examination as a predictor of preterm delivery. Am J Obstet Gynecol 1997; 177 (04) 723-730
- 5 Goya M, Pratcorona L, Merced C. et al; Pesario Cervical para Evitar Prematuridad (PECEP) Trial Group. Cervical pessary in pregnant women with a short cervix (PECEP): an open-label randomised controlled trial. Lancet 2012; 379 (9828): 1800-1806
- 6 Abdel-Aleem H, Shaaban OM, Abdel-Aleem MA. Cervical pessary for preventing preterm birth. Cochrane Database Syst Rev 2013; (05) CD007873
- 7 Nicolaides KH, Syngelaki A, Poon LC. et al. Cervical pessary placement for prevention of preterm birth in unselected twin pregnancies: a randomized controlled trial. Am J Obstet Gynecol 2016; 214 (01) 3.e1-3.e9
- 8 Cannie MM, Dobrescu O, Gucciardo L. et al. Arabin cervical pessary in women at high risk of preterm birth: a magnetic resonance imaging observational follow-up study. Ultrasound Obstet Gynecol 2013; 42 (04) 426-433
- 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 Goya M, Pratcorona L, Higueras T, Perez-Hoyos S, Carreras E, Cabero L. Sonographic cervical length measurement in pregnant women with a cervical pessary. Ultrasound Obstet Gynecol 2011; 38 (02) 205-209
- 12 Thangatorai R, Lim FC, Nalliah S. Cervical pessary in the prevention of preterm births in multiple pregnancies with a short cervix: PRISMA compliant systematic review and meta-analysis. J Matern Fetal Neonatal Med 2018; 31 (12) 1638-1645
- 13 Society for Maternal-Fetal Medicine (SMFM) Publications Committee. The role of cervical pessary placement to prevent preterm birth in clinical practice. Am J Obstet Gynecol 2017; 216 (03) B8-B10