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Type of suture used in cervical cerclage affects birth outcomes

Use of multifilament braided sutures in cervical cerclage procedures was linked to stillbirth and preterm birth, according to data published in Science Translational Medicine.

Lindsay M. Kindinger, MD, from the Imperial College Parturition Research Group at Imperial College London, and colleagues reported that women who received the braided sutures were three times more likely to experience nonviable births and nearly two times more likely to experience preterm birth.

"Cervical cerclage and progesterone supplementation are the only widely used clinical strategies for the prevention of [preterm birth], with an estimated 2 million cerclage procedures performed annually," the researchers wrote. "Cervical cerclage reduces the risk of [preterm birth] by about 20% in women with a history of spontaneous [preterm birth] and/or a short cervical length, and its use in these circumstances is recommended by both the American and the UK Royal College of Obstetricians and Gynecologists."

Kindinger and colleagues noted that, despite a lack of evidence, 80% of surgeons prefer using the multifilament braided sutures.

"Braided suture is composed of nonabsorbable polyester ethylene terephthalate fibers braided together to form a 5-mm-wide mesh tape," they detailed. "The tape is characteristically high in tensile strength and is thought to provide a secure structural support to a weakened cervix because of its high coefficient of friction. Monofilament sutures are made of a single strand of nonabsorbable polyamide polymer, and because of their simple structure, they provide less mechanical resistance when passed through tissue. As a result, they have a tendency to slip and therefore require a greater number of throws to secure the knot than a braided suture, which is why the braided suture is usually preferred."

The researchers conducted a retrospective study to assess birth outcomes among 678 women who received cervical cerclage at five hospitals.

They found that, compared to the monofilament suture, use of the multifilament braided suture was associated with increased intrauterine death (15% vs. 5%; P = .0001) and preterm birth (28% vs. 17%; P = .0006).

To understand the underlying mechanism, they also conducted a prospective, longitudinal study in 49 women at risk of preterm birth who received cervical cerclage.

The multifilament braided suture caused inflammation, as well as an imbalance in the vaginal microbiome, characterized by reduced Lactobacillus species and increased bacteria associated with poor pregnancy outcomes.

In comparison, the monofilament suture had little impact on the vaginal microbiome.

"Our data provide evidence that cervical cerclage using braided suture associates with increased rates of [preterm birth] and nonviable pregnancy," Kindinger and colleagues concluded. "Promotion of vaginal bacterial dysbiosis after insertion of braided structure material likely contributes to these adverse pregnancy outcomes through activation of local tissue inflammation and premature cervical remodeling. Because monofilament suture has minimal impact on the host microbiome or inflammation in pregnancy and associates with improved pregnancy outcome, we advocate its use for cervical cerclage." – by Chelsea Frajerman Pardes

Disclosures: Bennett serves as a consultant for ObsEva, a company that works in the field of preterm birth. Toozs-Hobson works as an advisor to Allergan, Specialty European Pharma, Astellas and Boston Scientific in areas not relevant to the current study. All other authors report no relevant financial disclosures.