What is the role of cerclage placement in the prevention of preterm labor?

Updated: May 04, 2021
  • Author: Michael G Ross, MD, MPH; Chief Editor: Carl V Smith, MD  more...
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Randomized clinical trials of cerclage for sonographically suspected cervical incompetence (shortened cervical length and/or funneling) have been inconclusive with respect to prevention of preterm delivery. [2] However, a history of midtrimester losses with loss of cervical integrity, often results in recommendation for cerclage placement between 13 and 17 weeks’ gestation. When the patient has a history of midtrimester loss after cone or LEEP biopsy therapy, prophylactic cerclage may be considered, but consulting with a maternal fetal medicine specialist may be beneficial due to the potential risks and the controversial proven benefit.

A meta-analysis of randomized trials in women with cervical length less than 25 mm on transvaginal ultrasonography found that cerclage significantly prevents preterm birth and composite perinatal mortality and morbidity in women with previous spontaneous preterm birth and singleton gestation. [14]

Simcox et al conducted a randomized controlled trial in 247 patients to determine if history or ultrasonography provided a better basis for whether women at risk of preterm birth should undergo cervical cerclage. Women treated on the basis of ultrasound criteria (cervical length < 20 mm) were significantly more likely to undergo cerclage (32% vs 19%; relative risk [RR] 1.66) and to receive progesterone (39% vs 25%; RR, 1.55) than were those treated on the basis of clinician preference. However, the rate of preterm delivery between 24 and 33 weeks was 15% in both groups. The results of this study showed that ultrasonographic screening of high-risk women to determine the need of cerclage resulted in more intervention but similar outcome compared with those determined to need cerclage based on history. [15]

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