What is the procedure and management for cervical encerclage in cases of suspected cervical insufficiency?

Cervical Cerclage for Cervical Insufficiency

Cervical cerclage is recommended for patients with a history of cervical insufficiency, particularly those with three or more second-trimester pregnancy losses or extreme premature deliveries without other identifiable causes. 1, 2

Definition and Indications

Cervical insufficiency exists on a spectrum, with some individuals showing cervical shortening before painless dilation or clinical signs such as labor or rupture of membranes 1. Cerclage placement is based on three main indications in singleton pregnancies:

• History-indicated cerclage: Recommended for women with a history of three or more second-trimester losses or extreme premature deliveries without other identifiable causes 2, 1
• Ultrasound-indicated cerclage: Considered in singleton pregnancies with prior spontaneous preterm birth if cervical length is ≤25 mm before 24 weeks gestation 2, 1
• Physical examination-indicated cerclage (emergency cerclage): May be considered when cervical dilation <4 cm occurs without contractions before 24 weeks gestation 2, 3

Procedure Types

There are several approaches to cervical cerclage:

• Transvaginal cerclage: Most commonly performed using either:

  • McDonald technique: A purse-string suture placed around the cervix at the level of the internal os 4, 3
  • Shirodkar technique: Involves placing the suture higher, with dissection of the bladder from the cervix 4, 3

• Transabdominal cerclage: Reserved for women with:

  • Failed previous transvaginal cerclage 2
  • Anatomical limitations preventing transvaginal approach 4
  • History of trachelectomy 2

Timing of Placement

• Elective/prophylactic cerclage: Typically placed at 12-14 weeks gestation 2
• Ultrasound-indicated cerclage: Placed when cervical shortening is detected before 24 weeks 1, 2
• Emergency cerclage: Performed when cervical dilation or membrane prolapse is detected before 24 weeks 5

Efficacy Based on Patient History

• With history of preterm birth: Compelling data show benefit of cerclage in patients with short cervix and previous preterm birth 1
• Without history of preterm birth: Cerclage has not generally demonstrated reduction in preterm birth rates 1
  • In patients with cervical length <25 mm without previous preterm birth, cerclage is not recommended 1
  • For patients with extremely short cervix (<10 mm), a subgroup analysis showed decreased preterm birth at <35 weeks (39.5% vs 58.0%; RR, 0.68) 1

Special Considerations

• Multiple gestations: Cerclage is not recommended in multiple gestations, even with history of preterm birth or short cervical length 2
• Cervical dilation with membrane prolapse: Emergency cerclage may be considered when cervix has dilated to <4 cm without contractions before 24 weeks 2, 5
• Extremely short cervix (<10 mm): Cerclage may be considered even without prior preterm birth history, based on shared decision-making 1

Management After Cerclage Placement

• Serial cervical length assessments: Not routinely recommended after cerclage placement due to insufficient evidence supporting clinical benefit 1
• Vaginal progesterone: May be beneficial after ultrasound-indicated cerclage placement, with one study showing reduced spontaneous preterm birth at <34 weeks (2.2% vs 18.4%) and <37 weeks (9.1% vs 29.7%) 1
• Bed rest: Not recommended routinely after cerclage placement 6
• Antibiotics and tocolysis: Routine use after cerclage placement is not recommended 6

Cerclage Removal

• Timing: Typically removed at 36-37 weeks gestation unless indicated earlier 6
• Preterm labor: Cerclage should be removed if preterm labor is established 6
• Preterm premature rupture of membranes (PPROM): Management is controversial - it is reasonable to either remove the cerclage or leave it in situ after discussing risks and benefits 1

Complications and Risks

• Preterm premature rupture of membranes: Can occur after cerclage placement, but emergency cerclage does not appear to increase this risk significantly 5
• Intrauterine infection/chorioamnionitis: A potential complication, particularly with emergency cerclage, though recent data suggests the risk may not be significantly increased 5
• Cervical trauma: Can occur during placement or removal 6

Outcomes

Emergency cervical cerclage in singleton pregnancies at 24-28 weeks has been shown to:

• Reduce adverse neonatal outcomes (8.33% vs 26.42% with conservative management) 5
• Significantly prolong gestational age (84.0 days vs 63.0 days with conservative management) 5
• Reduce preterm birth before 28,32, and 34 weeks 5