GTG 75 Cervical Cerclage

This post is the summary of GTG 75 Cervical Cerclage which was published in February 2022. This guideline supplements NICE 25 Preterm labour, GTG 73 PPROM and GTG 74 Antenatal corticosteroids. To prepare the topic comprehensively, it is advisable to read the other guidelines as well.

I hope this summary is helpful. 

Your feedback and suggestions to improve future posts are welcome.

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To download the guidelines 

• GTG 75 Cervical Cerclage
• GTG 74 Antenatal Corticosteroids
• GTG 73 PPROM Summary Click Here
• NICE 25 Preterm Labour Summary Click Here
• All GTGs Links

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Background

• Cerclage — a standard option for prophylactic intervention for those at risk of preterm birth & 2nd tri fetal loss
• Procedure to insert a stitch into cervix
• Aim is to prevent recurrent pregnancy loss
• Cervical insufficiency refers to weak cervix & unable to remain closed during pregnancy
• Cerclage provides structural support but maintaining cervical length more important

Definitions

History-indicated cerclage

• Insertion due to risk factors in patient’s history 
• Prophylactic measure in asymptomatic
• Usually @ 11-14 wks

Preterm birth PTB— Birth occurring <37+0 wks

USG-indicated cerclage

• Done if cervical shortening seen on scan
• Therapeutic measure in asymptomatic without exposed fetal membranes in vagina
• USG usually TVS b/w 14-24 wks (with empty bladder)

Emergency cerclage (AKA physical exam-indicated)

• Salvage measure 
• Inserted when premature cervical dilation with exposed fetal membranes in vagina
• Discovered by ultrasound or speculum/physical exam
• Considered up to 27+6 wks

Transvaginal cerclage (McDonald)

• Transvaginal purse-string suture placed at cervical isthmus junction without bladder mobilisation

High transvaginal cerclage requiring bladder mobilisation (including Shirodkar)

• Transvaginal purse-string suture after bladder mobilisation
• Inserted above cardinal ligaments

Transabdominal cerclage

• Suture via laparoscopy or laparotomy 
• Placed at cervico-isthmic junction

Occlusion cerclage

• Occlusion of external os by placing continuous non-absorbable suture
• Benefits by retaining mucous plug

History-indicated cerclage

When to offer?

• Singleton pregnancy + ≥ 3 previous PTB — significant reduction in preterm birth before 37, 34 & 28 wks No change in PMR neonatal morbidity
• Only effective if ≥3 PTB <37 wks — 50% reduction
• Not routinely offered if ≤3 PTB ± 2nd tri loss without additional risk factors
• No benefit in those with previous cervical surgery or uterine abnormalities

Ultrasound-indicated cerclage

When to offer?

• Not recommended if singleton pregnancy with no other risk factor for PTB having found short cervix incidentally 
• No overall benefit of cerclage with <25mm cx length with no other risk factors
• Routine surveillance for low risk not recommended

Singleton pregnancy & h/o PTB or spontaneous 2nd tri loss

• Undergoing USG surveillance — should be offered cerclage of cervix <25 mm at <24 wks
• Compared to expectant — Reduces pre-viable birth & perinatal death Does not prevent birth <35+0 wks unless length <15mm
• Cerclage not recommended for funnelling of cervix in absence of cervical shortening

Routine sonographic surveillance

• Having h/o PTB or 2nd tri spontaneous loss and not undergone history-indicated cerclage may be offered serial sonographic surveillance
• 40 - 70% women with h/o PTB or 2nd tri loss maintain cervical length >25 mm before 24 wks
• Those who maintain — 90% give birth after 34 wks
• If surveillance done — it helps in reducing the number of cerclage (only 42%)

	Group of woman	Recommendations
At high risk	Previous preterm birth or 2nd tri loss (16-34 wks) Previous PPROM <34 wks Previous use of cerclage Known uterine variant Intrauterin adhesions H/o trachelactomy	Review by preterm prevention specialist by 12 wks or with dating scan Offer TVS cervical scanning every 2-4 wks b/w 16-24 wks
At intermediate risk	H/o CS at full dilation Significant cervical excision surgery e.g. LLETZ with excision >1cm , >1 procedure or cone biopsy	Single TVS cervical scan no later than 18-22 wks as minimum

Cervical Cerclage for other groups at increased risk of preterm birth

Multiple Pregnancy

• History - or - ultrasound indicated cerclage — recommended
• No difference in perinatal death, neonatal morbidity or PTB <34 wks, CS
• USG-indicated cerclage associated with increased risk of LBW & RDS
• No intervention (progesterone, pessary or cerclage) significantly reduces risk of preterm birth

Cervical surgery, trauma and uterine abnormalities

• Local t/m of cervix — associated with increased risk of preterm birth
• Risk of PTB <37 wks — 
• Cold knife conization vs no t/m 14% vs 5%
• LLETz vs no t/m 11% vs 7%
• No increased risk with laser ablation
• CIN have increased background risk of PTB
• Risk higher if undergone more than one treatment & with increasing depth of excision 
• Recommendation by UK Preterm Clinical Network 
• With h/o LLETZ with >10mm excised or >1 LLETZ or cone biopsy should be referred to preterm birth prevention specialist AND single TVS cervical scan b/w 18-22 wks as minimum
• With known uterine variant —Refer to preterm prevention specialist by 12 wks and offer TVS cervical scanning every 2-4 wks b/w 16-24 wks

Raised BMI

• Cerclage effective in those with BMI >25 kg/m2 + having cervical length <25mm

Transabdominal Cerclage

When to consider?

• Usually inserted after an unsuccessful vaginal cerclage or extensive cervical surgery
• Rate of PTB <32 wks significantly lower in those with abdominal cerclage vs low vaginal cerclage 8% vs 33%
• NNT to prevent one PTB 3.9
• No difference in PTB b/w high & low vaginal cerclage
• Transabdominal cerclage can be preformed pre-conceptually or in early pregnancy — no difference in live birth rate among two
• Pre-conceptual preferable as lower risk of anaesthesia / has no effect on fertility
• Comparing abdominal with vaginal cerclage — no difference b/w time to conceive or rates of conception

Which approach?

• Laparoscopic & open abdominal have similar efficacy —no difference in rates of 2nd tri loss, birth after 34 wks, 3rd tri birth & live birth rates
• Similar fetal survival rates More complications in laparotomy (22% vs 2%)
• Laparoscopic approach considered if expertise available

Care for delayed miscarriage and fetal death

• Difficult decisions which should be aided by senior obstetrician 
• Complete evacuation through stitch by suction curettage or dilatation and evacuation (up to 18 wks) 
• Alternatively, suture may be cut
• If failed, hysterectomy or CS may be needed
• Offer appropriate counselling and signpost to relevant patient support groups
  

Emergency cerclage

When to offer?

• Individualised decision
• Balance b/w prolongation of pregnancy with reduced neonatal morbidity /mortality against possibility go prolonged severe neonatal morbidity
• Decision to be aided by senior obstetrician 
• Cerclage may delay birth by approx. 34 days (18-50) compared to expectant/bed rest alone
• 2-fold reduction of birth <34 wks
• Advanced dilation of cervix (>4 cm) or membrane prolapse associated with high chance of cerclage failure

Contraindication to cerclage insertion

• Active preterm labour
• Clinical chorioamniotis
• Continued vaginal bleeding
• PPROM
• Fetal compromise
• Lethal fetal defect
• Fetal death 

Information to given to women — Give verbal and written information

• Before ANY cerclage inform
• Small risk of intra-op bladder damage, cervical trauma, membrane rupture and bleeding 
• May be associated with cervical laceration/ trauma if spontaneous labour occurs
• High vaginal cerclage usually needs anaesthetic for removal
• Undergoing non-emergency cerclage inform
• Cerclage not associated with increased risk of PPROM, chorioamniotis, IOL or CS, increased risk PTB or 2nd tri loss
• May be associated with risk of cervical laceration/trauma if spontaneous labour and increased risk of maternal pyrexia

Pre-operative management

Investigations

• Before history-indicated cerclage — First tri USG and screening for aneuploidy
• Before ultrasound-indicated cerclage — Anomaly scan 
• Maternal WBC and CRP in emergency cerclage — CRP <4 mg/dl  WBC <14000/microlit associated with prolongation of pregnancy 

Role of amniocentesis 

• Insufficient evidence to recommend before rescue or USG-indiciated cerclage
• May be done in sleeted cases to aid management
• Some risk associated with procedure — does not increase risk of PTB <28wks

Amnioredcution — not recommended

Latency period b/w presentation & insertion of rescue or USG-indicated cerclage — individualised 

Genital tract screening —not to be done in routine if positive culture from genital swab → decide antibiotics on individual basis

Operative issues

Perioperative tocolytics —No recommended to be used in routine

Perioperative antibiotics — discretion of operating team

Anasthesia — discretion of operating team / case by case 

• Both GA & Regional can be used
• GA associated with shorter recovery time but higher demand for opoid and non-opioid analgesia 

Day-case procedure — can be preformed safely

Technique of cerclage — discretion of surgeon

• If used vaginal suture to be placed as high as possible
• No difference in PTB or perinatal outcome with McDonalds or Shirodkar

Suture —  use non-absorbable  (mersiline tape or polyester braided thread)

Cervical Occlusion — no benefit

Adjuvant management 

Bed rest — not recommended routinely

Sexual intercourse —  abstinence not recommended routinely

Role of post-cerclage serial sonographic surveillance 

• Not recommended in routine
• May be helpful in individual cases to offer timely steroids or in-utero transfer
• If history-indicated cerclage — additional USG-indicated cerclage not recommended in routine as it is associated with increase in pregnancy loss and birth before 35 wks 
• Emergency cerclage after elective or USG-indicated cerclage to be decided on individual basis

Fetal fibronectin testing after cervical cerclage — not recommended in routine has high NPV so may provide reassurance

Supplemental progesterone —  not recommended routinely

Arabian pessary or cerclage instead of cerclage —  either of these alone are less effective than cerclage 

When to remove cerclage?

Transvaginal cerclage to be removed before labour — usually b/w 36+1 - 37+0 wks unless birth by pre-labour CS (removal can be delayed until CS)

Established pre-term labour —Remove cerclage 

Anaesthesia needed to remove high vaginal cerclage

All with abdominal cerclage require birth by CS & leave the suture in place after birth

Cerclage and PPROM

PPROM 24-34 wks and without infection or PTL — delay removal of cerclage by 48 hrs (to facilitate in utero transfer)

Delayed suture removal until labour — associated with increased risk of maternal/fetal sepsis and is not recommended 

Before 23 wks and after 34 wks — delayed suture removal unlikely to be beneficial. 

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