Review Article| Volume 41, ISSUE 1, P76-88.e7, January 2019

Interventions to Try to Prevent Preterm Birth in Women With a History of Conization: A Systematic Review and Meta-analyses

Published:October 26, 2018DOI:



      The most effective preterm birth (PTB) intervention is unknown for women who are at risk of PTB due to a history of conization. The objective of this systematic review was to determine whether PTB interventions, progesterone, cerclage, and pessary decrease the risk of PTB compared to no treatment in singleton—and separately in twin—pregnancies of women with history of conization.


      We searched Cochrane Central, MEDLINE, EMBASE, CINAHL, and from January 1994 until May 2017. In duplicate, we reviewed titles, abstracts, full texts, extracted data, and assessed quality. We included RCTs and observational studies. Our primary outcomes were PTB <34 weeks, PTB <37 weeks, and neonatal mortality. We performed random effects meta-analyses and generated ORs with 95% CIs.


      We screened 762 nonduplicate titles and abstracts and assessed 91 full texts. After contacting authors, we included nine studies. Women in the cerclage group were more likely to have a short cervix or another risk factor for PTB, raising the possibility of confounding by indication. In women with a history of conization and a singleton who received a cerclage compared to those who did not, the ORs of PTB <34 weeks was 3.99 (95% CI 0.67–23.62, three studies, I2 = 65%); of PTB <37 weeks was 2.10 (95% CI 0.87–5.05, four studies, I2 = 0%); and of neonatal mortality was 8.33 (95% CI 0.22–320.38, two studies, I2 = N/A). We did not find any studies comparing either progesterone or pessary to no treatment. Data for twins were very scarce.


      In women with a previous conization and a current singleton gestation, the existing evidence, which is likely limited due to confounding by indication, does not support cerclage or other interventions used to try to decrease PTB.



      On ne sait pas quelle intervention est la plus efficace pour éviter les accouchements prématurés chez les femmes à risque en raison d’une conisation antérieure. L’objectif de cette revue systématique était de déterminer si les interventions, le cerclage ou l’utilisation de progestérone ou d’un pessaire diminuent le risque d’accouchement prématuré par rapport à l’absence de traitement dans les grossesses monofœtales – ainsi que gémellaires, séparément – chez les femmes ayant subi une conisation.


      Nous avons fait des recherches dans les bases de données Cochrane CENTRAL, MEDLINE, Embase, CINAHL et de janvier 1994 à mai 2017. Nous avons analysé les titres, les résumés et les textes complets, extrait les données et évalué la qualité deux fois. Nous avons inclus des ECR et des études observationnelles. Nos issues primaires étaient l’accouchement avant 34 semaines, l’accouchement avant 37 semaines et la mortalité néonatale. Nous avons effectué des méta-analyses à effets aléatoires et généré des rapports de cotes (RC) avec des intervalles de confiance à 95 %.


      Nous avons relevé 762 titres et résumés uniques et évalué 91 textes complets. Après avoir communiqué avec les auteurs, nous avons inclus neuf études. Les femmes dans le groupe de cerclage étaient plus susceptibles de présenter un col de l’utérus court ou un autre facteur de risque d’accouchement prématuré, ce qui augmentait la probabilité de confusion par indication. Si on comparait les femmes ayant déjà subi une conisation enceintes d’un seul fœtus qui avaient subi un cerclage à celles qui n’en avaient pas subi, le RC d’accouchement avant 34 semaines était de 3,99 (IC à 95 % : 0,67–23,62; trois études, I2 = 65%); celui d’accouchement avant 37 semaines était de 2,10 (IC à 95 % : 0,87–5,05; quatre études, I2 = 0 %); et celui de mortalité néonatale, de 8,33 (IC à 95 % : 0,22–320,38; deux études, I2 = s.o.). Nous n’avons pas trouvé d’études comparant l’utilisation de la progestérone ou d’un pessaire à l’absence de traitement. Les données pour les grossesses gémellaires étaient très limitées.


      Chez les femmes enceintes d’un seul fœtus ayant déjà subi une conisation, les données actuelles, qui sont vraisemblablement limitées en raison de la confusion par indication, n’appuient pas le cerclage ni les autres interventions utilisées pour tenter d’éviter les accouchements prématurés.

      Key Words


      17OHPC (17α-hydroxyprogesterone caproate), CIN (cervical intraepithelial neoplasia), GRADE (grading of recommendations assessment, development, and evaluation), LEEP (Loop electrosurgical excision procedure), LLETZ (large loop excision of the transformation zone), MD (mean difference), PTB (preterm birth)
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