Donate
Home » Am I at Risk?

Am I at Risk?

Many people associate uterine rupture only with a previous caesarean scar, but the reality is more complex. Less well-recognised risk factors exist, and rupture can occur in situations where risk is not routinely identified or considered.

This page outlines factors that may increase risk. Risk is not fixed, and it can change during pregnancy and labour. Understanding this helps families and care teams stay alert to symptoms and act early when needed.

Key Information

  • Risk depends on a combination of scar characteristics, medical history, pregnancy conditions, and labour management.
  • No single factor determines safety; risks are cumulative.
  • Some types of scars and surgical histories carry higher risk than others.
  • Induction and augmentation increase the risk of rupture, especially in scarred uteri.
  • Understanding these risks supports informed consent and safer birth planning.
1. Uterine Scars & Surgical History
Type of Previous Caesarean Section

The risk of rupture varies widely depending on the incision:

  • Low transverse incision: lower risk; suitable for VBAC under appropriate conditions.
  • Classical (vertical) incision: high risk; VBAC typically contraindicated.
  • T or J extensions: increased risk depending on depth and location.
  • Fundal or upper-segment incisions: high risk; elective caesarean recommended.

Scar locations

Other Uterine Interventions

Procedures involving the myometrium can weaken the uterine structure:

  • Myomectomy
  • Metroplasty
  • Septum resection
  • Hysteroscopic perforation
  • Intensive D&C’s
  • Previous rupture repair

The depth and number of incisions are important predictors of risk.

Quality of Scar Healing

Factors that may compromise healing include:

  • Single-layer closure
  • Infection after surgery
  • Haematoma or delayed wound healing
  • Caesarean scar defects (isthmocele)

Women with known scar defects or very thin residual myometrium may have elevated rupture risk and may be advised against TOLAC.

Inter-Pregnancy Interval

A short interval between pregnancies or surgery may increase rupture risk because the scar has not fully remodelled. It is generally recommended to wait 12 months between a caesarean section and conception.

Müllerian Anomalies

Uterine malformations (such as bicornuate, septate, unicornuate, or didelphys uteri) are still poorly researched, but current understanding suggests that they may:

  • Create areas of focal weakness within the uterine wall
  • Alter how pressure is distributed as the uterus expands or contracts during labour
  • Increase the risk of uterine rupture, even in the absence of a prior surgical scar

Connective-Tissue Disorders

Conditions such as Ehlers–Danlos or Marfan syndrome may:

  • Reduce collagen strength
  • Impair scar healing
  • Increase susceptibility to uterine distension and tearing

Cesarean Scar Defects (Isthmocele)

An isthmocele may:

  • Significantly weaken the lower uterine segment
  • Increase risk of rupture or dehiscence
  • Complicate induction decisions

Endometriosis, Adenomyosis & Fibroids

These conditions may affect tissue quality and contribute to abnormal healing or focal thinning of the myometrium.

Induction of Labour

Induction is consistently associated with higher rupture risk in scarred uteri, especially with:

  • Prostaglandins (including misoprostol/cytotec)
  • High-dose or aggressive oxytocin
  • Combined mechanical + pharmacological methods

Even low-dose oxytocin carries elevated risk compared to spontaneous labour.

Augmentation of Labour

Increasing contractions through oxytocin infusion raises intrauterine pressure, which may stress a weak scar.

Prolonged or Obstructed Labour

Risk increases when:

  • Labour progresses unusually slowly
  • The baby is malpositioned
  • Contractions are strong but ineffective
  • Hyperstimulation is present

Placental Positioning

  • A low-lying placenta or placenta previa over a uterine scar may indicate abnormal implantation and reduced scar integrity.

  • Placenta accreta spectrum disorders, in which the placenta abnormally attaches to or invades the uterine wall, are associated with weakened uterine tissue and an increased risk of rupture.

Fetal Factors

Large babies (macrosomia) and malpresentation (breech, transverse, brow) increase contractions and mechanical stress.

Over-Distension of the Uterus

High parity or a history of prolonged labour may weaken the uterine wall over time. Repeated stretching and sustained pressure can reduce the uterus’s ability to withstand stress, similar to tissue that has been overstretched repeatedly.


Over-distension may occur in the following situations:

  • Polyhydramnios

  • Fetal macrosomia

  • High parity

  • Multiple pregnancy

Maternal Health Factors

Risk may increase with:

  • Advanced maternal age
  • Gestational diabetes
  • Hypertension or pre-eclampsia
  • Obesity or low BMI, depending on context

  •  

  •  

  •  

These factors may affect tissue strength, healing, or labour progression.

A history of uterine rupture is one of the strongest predictors of recurrence.

  • Recurrence risk varies depending on location and repair quality.
  • Women with prior rupture are generally advised to have a scheduled caesarean before labour begins.
  • Individualised assessment is essential.

What Happens During a Rupture?

Understanding your personal risk is the first step. The next page, What Happens During a Rupture, explains the physical event itself: what occurs inside the uterus, how blood flow is disrupted, how the fetus is affected, and why rapid intervention is critical.

This clear breakdown helps families and clinicians recognise the urgency of rupture and understand why each risk factor matters.

Next Page