Cerclage Linked to Higher Newborn Survival Rate

Tara Haelle

June 10, 2015

Cerclage placement, when indicated by physical examination, significantly increases neonatal survival and extends pregnancy by an average of 33.98 days compared with expectant management, according to a systematic review and meta-analysis published online June 5 and in the July issue of Obstetrics & Gynecology. The researchers also found fewer preterm births and higher birth weights associated with physical exam–indicated cerclage, although only one randomized trial was available for the analysis.

"A concern with physical examination–indicated cerclage is that it may prolong pregnancy long enough only to result in an extremely preterm delivery," note Robert Ehsanipoor, MD, from the Department of Gynecology and Obstetrics at Johns Hopkins University in Baltimore, Maryland, and colleagues. "However, we found that expectant management was associated with a more than fourfold increased risk of delivery between 24 and 28 weeks of gestation."

They continue, "[T]he current literature suggests that physical examination–indicated cerclage is associated with markedly improved outcomes."

Still, an important caveat of their analysis includes the limited quality and small size of the included studies. The researchers searched six databases for studies published between 1966 and 2014 that compared cerclage with expectant management for treating cervical insufficiency. Cervical insufficiency, defined as painless second semester cervical dilation, occurs in less than 1% of pregnancies, and few data exist for assessing the benefit of cerclage to prevent pregnancy loss.

The authors included studies that required at least 0.5-cm cervical dilatation in women between 14 and 27 weeks' gestation. They identified 10 studies, including two prospective cohort studies, seven retrospective cohort studies, and just one randomized controlled trial, which included 23 pregnancies. Among the combined 757 women across all the studies, 64% underwent cerclage placement and 36% received expectant management. Participants did not significantly differ in age, nulliparity, or preterm birth history, and all women's membranes were visible or prolapsed in all but one of the studies.

Overall, 71% of newborns survived in the cerclage group compared with 43% of those in the expectant management group (relative risk [RR], 1.65; 95% confidence interval [CI], 1.19 - 2.28), according to the eight studies that reported survival outcomes.

Pregnancies in the cerclage group lasted a mean 33.98 days longer than those in the expectant management group (95% CI, 17.88 - 50.08 days), and infant's gestational ages at delivery in the cerclage group were a mean 4.62 weeks older (95% CI, 3.89 - 5.36 weeks).

In a subanalysis of the three studies at lowest risk for bias, which included 64 women with cerclage and 42 women under expectant management, likelihood of neonatal survival in the cerclage group was even greater (78% vs 33%; RR, 2.11; 95% CI, 1.41 - 3.55). Pregnancy prolongation, though, was similar at 34.00 days, as in the larger analysis (95% CI, 3.11 - 64.89 days).

In the full analysis, rates of preterm birth between 24 and 28 weeks' gestation (8% vs 37%; RR, 0.23; 95% CI, 0.13 - 0.41) and at less than 34 weeks' gestation (50% vs 82%; RR, 0.55; 95% CI, 0.38 - 0.80) were also lower in the cerclage group. Birth weights were a mean 1028 g greater in the cerclage group (95% CI, 714 - 1,341 g).

The authors have disclosed no relevant financial relationships.

Obstet Gynecol. Published online June 5, 2015. Abstract.


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