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

Cervical Cerclage for Cervical Insufficiency

Cervical cerclage is strongly recommended for patients with a history of three or more second-trimester pregnancy losses or extreme premature deliveries without other identifiable causes. 1

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
• Cervical cerclage is the primary treatment for cervical insufficiency, effectively preventing late miscarriage and preterm birth 2
• There are three main indications for cerclage in singleton pregnancies:
  • History-indicated cerclage (prior multiple early preterm births or second trimester losses) 3
  • Ultrasound-indicated cerclage (cervical length <25 mm before 24 weeks in women with prior spontaneous preterm birth) 3
  • Physical examination-indicated cerclage (cervical dilation on examination before 24 weeks) 3

Types of Cervical Cerclage

• Prophylactic (elective) cerclage: Performed at 12-14 weeks gestation for women with history of cervical insufficiency 4, 5
• Therapeutic cerclage: Includes urgent cerclage (for ultrasound-detected short cervix/funneling at 16-20 weeks) and emergent cerclage (for asymptomatic cervical dilation ≥2 cm or membrane prolapse) 4
• Cerclage can be performed transvaginally (usually McDonald technique) or transabdominally 4
• Abdominal cerclage should be considered when prior vaginal cerclage has failed or in women who have undergone trachelectomy 5

Patient Selection

• Women with a history of three or more second-trimester losses or extreme premature deliveries without other identifiable causes should be offered elective cerclage at 12-14 weeks 1, 5
• Cerclage should be considered in singleton pregnancies with history of spontaneous preterm birth if cervical length is ≤25 mm before 24 weeks 5
• Emergency cerclage may be considered in women with cervical dilation <4 cm without contractions before 24 weeks 5
• Women with 1-2 prior mid-trimester losses or extreme premature deliveries should be offered serial cervical length assessment by ultrasound 5

Contraindications and Cautions

• Cerclage is not beneficial in multiple gestations, even with history of preterm birth 5
• Cerclage is not recommended for women with incidental finding of short cervix without prior risk factors for preterm birth 5
• Cerclage placement should not be based on cervical length in multiple gestations 5

Management After Cerclage Placement

• Serial cervical length assessments are 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, routine use of antibiotics, tocolysis, and progesterone are generally discouraged after cerclage placement 6

Cerclage Removal

• Management of preterm premature rupture of membranes (PPROM) is controversial - it is reasonable to either remove the cerclage or leave it in situ after discussing risks and benefits 1
• Cerclage should be removed in case of established preterm labor 6
• Typically, cerclage is removed at 36-37 weeks gestation to prevent cervical trauma during labor 1

Outcomes and Efficacy

• Emergency cervical cerclage in singleton pregnancies at 24-28 weeks can reduce adverse neonatal outcomes (8.33% vs 26.42% with conservative treatment) 2
• Emergency cerclage significantly prolongs gestational age (84.0 days vs 63.0 days with conservative treatment) 2
• Emergency cerclage reduces preterm birth before 28,32, and 34 weeks without increasing risk of premature rupture of membranes or intrauterine infection 2

Common Pitfalls and Caveats

• Infection screening is essential - urinalysis and vaginal cultures for bacterial vaginosis should be taken at the first obstetric visit and infections treated 5
• The effectiveness of cerclage varies based on indication and patient history - strongest evidence exists for history-indicated cerclage in women with ≥3 prior losses 1, 5
• Cerclage may not be beneficial in all cases of short cervix - patient history and risk factors must be considered 1, 5
• There is still debate regarding the role of amniocentesis in ruling out intra-amniotic infection before rescue cerclage 6