Definitions

• CI is the inability of the cervix to retain a pregnancy in the absence of contractions (painless cervical dilation).

Incidence and Significance

• CI, or cervical incompetence, occurs in 1 in 100 to 1 in 2,000 gestations.

Risk Factors

• Risk factors include prior cervical laceration, history of cervical conization, multiple terminations with mechanical cervical dilation, intrauterine diethylstilbestrol exposure, and congenital cervical anomaly.

Management

Indications for cervical cerclage as defined by ACOG are outlined in Table 8-3.

• History-indicated (prophylactic) cerclage is typically placed at 12 to 14 weeks' gestation.

• Examination-indicated (emergent/rescue) cerclage is placed at time of diagnosis, but must first rule out preterm labor and intra-amionic infection. Typically not placed after viability and depends on individual case and shared decision making.

• Ultrasound-indicated cerclage is placed at time of diagnosis. Typically not placed after viability and depends on individual case and shared decision making.

  Table 8-3 Indications for Cervical Cerclage in Women With Singleton Pregnancies

  History History of one or more second-trimester pregnancy losses related to painless cervical dilation and in the absence of labor or abruptio placentae Prior cerclage due to painless cervical dilation in the second trimester

  Physical Examination Painless cervical dilation in the second trimester

  Ultrasonographic Finding With a History of Prior Preterm Birth Current singleton pregnancy, prior spontaneous preterm birth at less than 34 weeks of gestation, and short cervical length (less than 25 mm) before 24 weeks of gestation

  Reprinted with permission from Cerclage for the management of cervical insufficiency. Practice Bulletin No. 142. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2014;123(2 Pt 1):372–379. Copyright © 2014 by The American College of Obstetricians and Gynecologists.

• There is no current evidence to support cerclage in multifetal gestation.

• Vaginal cerclage may be performed either using the McDonald or Shiradkor techniques. Permanent suture, either Prolene (polypropylene) or Mersiline (polyester fiber) are commonly employed. Prophylactic antibiotics and postoperative tocolytics have not been proven to affect outcome, except possibly in the case of rescue cerclage where such use is associated with a higher percentage of patients with pregnancies prolonged by at least 28 days.

• The risk of iatrogenic pregnancy loss ranges from 1% to 20% for nonrescue cases. Rescue cerclage for CI/bulging membranes is associated with >50% risk of complications.

  • Transvaginal cervical cerclage removal is indicated at 36 to 37 weeks' gestation and removal is not an indication for delivery.

  • Patients who will undergo cesarean section at 39 weeks may keep cerclage in place until that time with removal at the time of surgery. However, clinician must weigh risks of cervical trauma if preterm or early-term contractions occur and counsel patients regarding signs of labor.

• Abdominal cerclage may be considered in patients with minimal to no residual cervical length (often due to large cone biopsies or trachelectomy) or previous failed transvaginal cervical cerclage (ie, previous placement in pregnancy that ultimately resulted in second trimester pregnancy loss).

  • Performed in late first trimester and early second trimester or in nonpregnant patient via laparotomy or using minimally invasive (laparoscopic or robotic methods) techniques.

  • May be kept in place between pregnancies with planned cesarean deliveries.

  • Subsequent cesarean section is necessary in the setting of an abdominal cerclage.

• Vaginal progesterone as described in Preterm Labor section.