CLINICAL ACTIONS:

ACOG defines cervical insufficiency as “the inability of the uterine cervix to retain a pregnancy in the absence of the signs and symptoms of clinical contractions, or labor, or both in the second trimester.” In addition, ACOG separates out indication for cerclage in to 3 categories

• History: ≥1 of the following
  • Second trimester pregnancy losses related to painless cervical dilation and no history of labor or abruption
  • Previous second trimester cerclage for painless cervical dilation
• Physical Examination: Also known as ‘physical examination–indicated cerclage’, ‘rescue cerclage’ and ’emergency cerclage’
  • Patient presents with painless second trimester cervical dilation
• Ultrasound: Cervical length shortening and history of preterm birth
  • Singleton pregnancy
  • Prior spontaneous preterm birth (<34 weeks)
  • Cervical length:  <25 mm (at <24 weeks)

SMFM states that cerclages are effective in woman based on the following indications:

• History indicated: 3 or more PTBs or second-trimester losses.
• Ultrasound indicated: ≥1 early PTB (defined as delivery between 17w to 33w6d), and cervical length (CL) <25 mm on transvaginal ultrasound (TVUS) before 24 weeks

Timing of Cerclage Placement

• History-indicated cerclage
  • Place between 12 and 14 weeks after confirmation of pregnancy viability
• Ultrasound or exam-indicated cerclage
  • May be placed prior to 23 weeks

Risk Factors

• Prior PTB
• Repeated cervical dilation
• Cervical procedures (including cone and LEEP)
• Cervical laceration
• Urogenital abnormalities

SYNOPSIS:

Clinically, cervical insufficiency is painless dilation and recurrent mid-trimester losses without signs of preterm labor (PTL), PPROM, or infection. Patient history may include superimposed symptoms (i.e. bleeding, pressure), therefore a judicious review of records is advised.  Those with a history of prior preterm birth can benefit from cervical length screening to appropriate guide selected patients for cerclage.

KEY POINTS:

Ultrasound Indicated Cerclage with Prior History of Preterm Birth or Second Trimester Losses (SMFM)

• CL surveillance
  • Begin at 16 weeks
  • Perform every 2 weeks
  • CL measurement 25-29 mm: Perform weekly
• Offer cerclage when
  • CL <25 mm prior to 23w0d weeks and
  • History of spontaneous PTB at 17w0d to 33w6d
• 17–alpha hydroxyprogesterone caproate (17-OHPC)
  • Note: Cerclage placement or presence should not alter recommendations
• Evidence from research studies
  • There is no difference in efficacy of McDonald versus Shirodkar techniques

Special Circumstances

• Diagnosis of cervical insufficiency is unclear
  • Consider close screening starting at 16 weeks in place of history indicated cerclage placement
• Very early losses
  • Consider beginning screening <16 weeks if there is a history of very early second trimester losses

‘Emergency’ Cerclage (Exam indicated)

• There is literature, including a meta-analysis (Obstet Gynecol, 2015), to support ’emergency’ or ‘rescue’ cerclage
  • Neonatal survival
    • Cerclage: 71% survival
    • No cerclage: 43% survival
    • Relative risk 1.65 (95% CI 1.19–2.28)
  • Prolongation of pregnancy
    • Mean difference: 33.98 days (95% CI, 17.88 to 50.08)
  • Authors note significant limitations including quality of data and only 1 RCT included

After clinical examination to rule out uterine activity, or intraamniotic infection, or both, physical examination-indicated cerclage placement (if technically feasible) in patients with singleton gestations who have cervical change of the internal os may be beneficial

SMFM Choosing Wisely Campaign

• SMFM recommends the following after cerclage placement
  • Do not perform serial cervical length measurements
  • There is no evidence that cervical length monitoring following a cerclage improves outcomes, despite cervical shortening being associated with increased risk for preterm birth

Learn More – Primary Sources:

SMFM: Cervical cerclage for the woman with prior adverse pregnancy outcome

ACOG Practice Bulletin 142: Cerclage for the Management of Cervical Insufficiency

Physical Examination–Indicated Cerclage: A Systematic Review and Meta-analysis

Related ObG Topics:

Meta-analysis: Cerclage for Short Cervix but Without History of Preterm Birth 

Progesterone or Cerclage in Preterm Prevention in Women with Previous Preterm Birth and Short Cervix?

SMFM Statement: Choice of Progestogen for Preterm Birth Prevention

The Role of Routine Cervical Length Screening For Preterm Birth Prevention

SMFM and Choosing Wisely: Practices That Doctors and Patients Should Question