Uterine Rupture

Key points

  • True uterine rupture is a catastrophic event with significant associated maternal and fetal morbidity and mortality.
  • Reports of morbidity due to uterine rupture may have contributed to a decrease in the number of women attempting vaginal birth after caesarean section.
  • There have been no prospective national studies to estimate the incidence or outcomes of uterine rupture.
  • This study will investigate the incidence, management and outcomes for mother and infant of uterine rupture. It will in addition investigate the risks associated with induction and augmentation of labour in women who have had a previous caesarean delivery.

Surveillance Period

April 2009 – April 2010

Background

True uterine rupture is a catastrophic event with significant associated maternal and fetal morbidity and mortality. In the developed world it most commonly occurs in women who have previously delivered by caesarean section[1]. This observation has led to debate about the optimal management of labour and delivery in women who have delivered by caesarean section in previous pregnancies. Women with a previous caesarean delivery have generally been encouraged to attempt a trial of labour in subsequent pregnancies[2], but reports of an increased risk of morbidity, particularly due to uterine rupture, are thought to have contributed to a decrease in the number of women attempting vaginal birth after caesarean section[3]. The rate of caesarean section delivery in the UK is increasing, with previous caesarean section being the most common primary obstetric indication for repeat caesarean[4]. Two recent systematic reviews have attempted to quantify the incidence of uterine rupture[1][5]. Both these reviews identified a number of deficiencies in the few existing studies in developed countries and suggested that a prospective national study of uterine rupture would offer the best opportunity to guide preventive strategies. They identified only one previous UK population-based study[6], which reported 12 ruptures in 48,865 deliveries, a rate of approximately 1 in 4000 deliveries.

In addition to difficulties in quantifying the incidence of uterine rupture, Guise et al[5] noted that existing observational studies were insufficient to answer additional questions about the risks of rupture associated with induction and augmentation of labour. This prospective, descriptive study using the UK Obstetric Surveillance System will address these questions and quantify the national incidence of uterine rupture in the UK.

Objectives

  • To use the UK Obstetric Surveillance System to describe the epidemiology of uterine rupture in the UK.
  • To determine what proportion of ruptures are associated with prior delivery by caesarean section.

Research questions

  • What is the current incidence of uterine rupture in the UK?
  • What are the characteristics of women who suffer from uterine rupture?
  • What proportion of ruptures occur in women who have previously delivered by caesarean section?
  • What is the risk associated with labour induction or augmentation of labour after prior delivery by caesarean section?
  • What are the outcomes for mother and infant?

Case definition

Any woman in the UK identified as having a uterine rupture using the following definition[5][7]:

A complete separation of the wall of the pregnant uterus, with or without expulsion of the fetus, involving rupture of membranes at the site of the uterine rupture or extension into uterine muscle separate from any previous scar, and endangering the life of the mother or fetus.

Excluded: any asymptomatic palpable or visualised defect (for example dehiscence noted incidentally at caesarean delivery).

Funding

Wellbeing of Women

Ethics committee approval

The study has been approved by the London MREC (study ref 09/H0718/8).

Investigators

  • Marian Knight, Jennifer Kurinczuk, Peter Brocklehurst, NPEU
  • Zarko Alfirevic, University of Liverpool

Download the Data Collection Form (DCF)

UKOSS Uterine Rupture Form

References

  1. a, b Hofmeyr GJ, Say L, Gulmezoglu AM. WHO systematic review of maternal mortality and morbidity: the prevalence of uterine rupture. BJOG 2005; 112(9):1221-8.
  2. ^ National Collaborating Centre for Women's and Children's Health. Caesarean Section. London: RCOG, 2004.
  3. ^ Dodd JM, Crowther CA, Huertas E, Guise JM, Horey D. Planned elective repeat caesarean section versus planned vaginal birth for women with a previous caesarean birth. Cochrane Database Syst Rev 2004; (4):CD004224.
  4. ^ RCOG Clinical Effectiveness Support Unit. The National Sentinel Caesarean Section Audit Report. London: RCOG, 2001.
  5. a, b, c Guise JM, McDonagh MS, Osterweil P, Nygren P, Chan BK, Helfand M. Systematic review of the incidence and consequences of uterine rupture in women with previous caesarean section. BMJ 2004; 329(7456):19-25.
  6. ^ Waterstone M, Bewley S, Wolfe C. Incidence and predictors of severe obstetric morbidity: case-control study. BMJ 2001; 322(7294):1089-93; discussion 1093-4.
  7. ^ Cowan RK, Kinch RA, Ellis B, Anderson R. Trial of labor following cesarean delivery. Obstet Gynecol 1994; 83(6):933-6.