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Transabdominal cerclage

Key points

  • Spontaneous preterm birth is a leading cause of perinatal morbidity and mortality.
  • Cervical insufficiency often results in preterm birth.
  • Transabdominal cerclage (TAC) is a surgical procedure that can be used to treat cervical insufficiency.
  • TAC insertion is increasing in the UK, therefore it is important to understand how to manage women who have a TAC in situ.

Surveillance period

1st May 2024 - 30th April 2025


Preterm birth, defined as birth before 37 weeks of gestation, is arguably the most important challenge facing modern obstetrics, accounting for almost 8% of all live births in England and Wales and contributing to much neonatal and infant morbidity and mortality.1 Cervical insufficiency, caused by structural weakness in the cervix making it unable to remain closed during pregnancy, greatly increases the risk of preterm birth. Clinically, once a woman has been identified as being at risk of preterm birth due to short cervical length, a cervical cerclage (a suture placed around the cervix) may be recommended. The majority of cerclages are undertaken vaginally as this is less invasive; however in women with a previous failed vaginal stitch or insufficient cervical tissue, insertion of a TAC may be offered.2 TACs are more complex to insert (placed higher, closer to the internal os) and require more intervention, but little is known about their safety or effectiveness and they are not always made available to all suitable women.3

As TAC is becoming a more commonly-practised intervention in the UK, understanding the incidence of insertion, indications for insertion, management of pregnancy complications, maternal and neonatal outcomes and procedure-related complications will facilitate an improved knowledge-base and more reliable counselling of women who may be eligible to receive the intervention.


To use the UK Obstetric Surveillance System (UKOSS) to describe the incidence of TAC in the UK and examine subsequent management and outcomes.

Research questions

  • What is the current annual incidence of pregnant women with TAC in situ in the UK?
  • What are the indications for insertion of TAC?
  • What proportion of women with a TAC in situ have pregnancy complications and how are they managed?
  • What are the pregnancy and early neonatal outcomes of women with a TAC in situ?

Case definition

Any pregnant woman who presents to an obstetric unit with a transabdominal cerclage in situ.


This study is funded by Tommy's Charity.

Ethics committee approval

This study has been approved by the London Brent REC (Ref. Number 10/H0717/20).

Lead investigators

Dr Manju Chandiramani, Guy's and St Thomas' NHS Foundation Trust;

Professor Andrew Shennan and Dr Natalie Suff, King's College London School of Life Course Sciences;

Dr Jenny Carter and Miss Naomi Carlisle, Department of Women and Children's Health, King's College London;

Miss Joanne Deery, PPI representative


  2. Shennan AH, Story L; the Royal College of Obstetricians, Gynaecologists. Cercvical Cerclage. BJOG 2022; 129:1178-1210
  3. Shennan A, Chandiramani M, Bennett P, et al. MAVRIC: a multicentre randomised controlled trial of transabdominal vs tansvaginal cervical cerclage. Am J Obstet Gynecol. 2020 Mar; 222(3):261.e1-261.e9. doi:10.1016/j.ajog.2019.09.040. Epub 2019 Oct 1.Am J Obstet Gynecol. 2020.

Updated: Tuesday, 23 April 2024 10:44 (v2)