# ABOVE: cerclage after caesarean: protocol for a randomised controlled trial to assess the optimal preventative management for preterm birth secondary to caesarean section damage

## TL;DR

This study compares two types of cervical support procedures to prevent preterm birth in women who had a caesarean section and later pregnancy complications.

## Contribution

The study introduces a trial comparing transabdominal and transvaginal cerclage for preventing preterm birth after caesarean-related cervical damage.

## Key findings

- The trial will assess the effectiveness of transabdominal versus transvaginal cerclage in preventing preterm birth.
- It will inform evidence-based guidelines for managing high-risk pregnancies following caesarean-related cervical damage.
- The study addresses the growing issue of preterm birth linked to prior caesarean section damage.

## Abstract

There is emerging evidence that caesarean section in labour is associated with an increased risk of recurrent mid-trimester loss (MTL) and spontaneous preterm birth (sPTB) in subsequent pregnancies. This is likely due to inadvertent damage to the cervical tissue at the time of caesarean section. Transvaginal cerclage (TVC) has been demonstrated to be less successful in this high-risk cohort of women. However, transabdominal cerclage (TAC) may be more effective as the suture is placed above the level of cervical caesarean damage. A TAC can be placed before or during early pregnancy, although placement during pregnancy may be less effective. To determine the optimal clinical management for women with this risk factor, the ABOVE trial will evaluate the effectiveness of TAC compared to TVC in women who have experienced a MTL or sPTB following an in-labour caesarean section.

ABOVE is a multicentre randomised control trial comparing TAC or TVC as a preventative strategy for sPTB in women with history of an in-labour CS and subsequent MTL (14+ 0 -23+ 6 weeks) or sPTB (< 30 weeks). Participants will be allocated to one of two groups - Group A (currently pregnant < 14 weeks’ gestation) and Group B (planning a pregnancy) - and randomised 1:1 to TAC or TVC within each group.

The ABOVE trial will investigate the efficacy of known interventions in the prevention of preterm birth, TVC and TAC, in women who have had a previous in-labour CS and subsequent MTL or sPTB. The trial will inform the development of evidence-based practice guidelines to optimise the care offered to this cohort of high-risk women. With escalating rates of CS and the increased recognition of the relationship between caesarean cervical damage and sPTB and MTL, this work is key.

ISCRTN 10977996 (17/05/2024).

The online version contains supplementary material available at 10.1186/s12884-026-08816-9.