Classification

• Occult or incomplete rupture is where a surgical scar separates but the visceral peritoneum stays intact. It is usually asymptomatic and does not require emergency surgery.
• Complete rupture can be:
  • Traumatic:
    • Motor vehicle accident.
    • Incorrect use of oxytocic agent .
    • Poorly conducted attempt at operative vaginal delivery (typically breech extraction with an incompletely dilated cervix).
  • Spontaneous:
    • Most patients either have had Caesarean section or a history of trauma that could have caused permanent damage.¹
    • Patients may have no history of surgery but a weakened uterus due to multiparity, particularly if they have an old lateral cervical laceration.

Epidemiology

Incidence

Occurs in 0.4-0.6 of all deliveries.²

Risk factors

• Prior uterine surgery (including myomectomy, vigorous curettage, induced abortion, manual removal of the placenta). However, the most frequent cause of a uterine scar is a previous Caesarean section. Classical vertical and T-shaped incisions carry a higher risk of later uterine rupture than the standard modern low transverse approach.
• Uterine anomalies (e.g. undeveloped uterine horn).
• Trauma, e.g. vehicle accident.
• Use of rotational forceps.
• Obstructed labour.
• Induction of labour (suspected association only) - prostaglandins should be used with caution during a trial of labour.
• Cervical laceration.
• Placenta percreta or increta.
• Hydramnios.
• Macrosomia and fetal anomaly, e.g. hydrocephalus.
• Malpresentation (brow or face).
• Multiple pregnancy.
• Choriocarcinoma.

Other procedures with high risk of uterine rupture include internal podalic version and extraction, destructive operations and manoeuvres to relieve shoulder dystocia.

Presentation

Management of uterine rupture depends on prompt detection and diagnosis:

• The classic signs (sudden tearing uterine pain, vaginal haemorrhage, cessation of uterine contractions, regression of the fetus) have been shown to be unreliable and frequently absent.³
• Prolonged, late or variable decelerations and bradycardia seen on fetal heart rate monitoring are the most common and often the only manifestations of uterine rupture. In 3/4 of cases, signs of fetal distress will appear before pain or bleeding.
• Sudden appearance of gross haematuria is indicative of rupture.
• Increasing pain and bleeding may occur as the size of rupture increases with possible signs of hypovolaemic shock and haemoperitoneum. Exsanguination prior to surgery is unlikely (because of reduced vascularity of scar tissue) unless a uterine artery has been lacerated, but the placenta may completely separate and the fetus pass either partially or totally out of the uterus and into the abdominal cavity with a high risk of intrapartum death.

Laparotomy may still be required even after a successful vaginal delivery, if there is suspicion of uterine rupture, to assess damage and to control bleeding.

Investigations

• Ultrasound can show an abnormal fetal position or extension of fetal extremities or haemoperitoneum.
• Intrauterine pressure catheters are sometimes used but may fail to show loss of uterine tone or contractile patterns following uterine rupture.

Management

• In all cases of operative delivery, especially where there are risk factors for uterine rupture, a thorough examination of the uterus and birth canal is required.³
• In most cases of complete uterine rupture, hysterectomy is the preferred treatment - either total or sub-total, depending on the site of rupture and the patient's condition.
• In cases of lateral rupture involving lower uterine segment and uterine artery where haemorrhage and haematoma obscure the operative field, ligation of the ipsilateral hypogastric artery to stop bleeding may be needed.
• Where future child-bearing is important and risks are acceptable, rupture repair can be attempted. Repeat rupture occurs in approximately 20% of cases.

Complications

• Postoperative infection.
• Damage to ureter.
• Amniotic fluid embolus.
• Massive maternal haemorrhage and disseminated intravascular coagulation (DIC).
• Pituitary failure.

Prognosis

• 4.2% maternal mortality.⁵
• 46% perinatal mortality and morbidity.⁶

Prevention

Unfortunately, uterine rupture cannot be adequately predicted for women wanting a trial of labour following a previous Caesarean section.⁷ Doctors should review the medical history for risk factors and counsel regarding her relative risks, benefits, alternatives and probability of success.³ Usually, shared care undertaken with an obstetrician is appropriate for any woman with a previous section.

A few circumstances (prior classic or T-shaped incision, contracted pelvis, unavailability of facilities for emergency Caesarean delivery) will preclude a trial of labour. In most instances, however, the decision about mode of birth following a previous Caesarean should take into consideration:⁸

• Maternal preferences and priorities.
• A general discussion of overall risks and benefits of Caesarean section.
• Risk of uterine rupture - uterine rupture is a rare complication even in those who have had a previous Caesarean. (The rate of uterine rupture for all women with prior Caesarean is 3 per 1,000; the risk is significantly increased with a trial of labour - 4.7/1,000.)⁹
• Risk of perinatal mortality and morbidity: the risk of an intrapartum death is small in planned vaginal birth (10 per 10,000) but higher than those having a planned repeat Caesarean (1 per 10,000). The effect of planned vaginal birth or repeat Caesarean section on cerebral palsy is uncertain.

Those who opt for a trial of labour should be offered continuous electronic fetal monitoring during delivery and care during labour in a unit where there is immediate access to emergency Caesareans and an on-site blood transfusion service. Ideally, delivery should take place in a unit with more than 3,000 births per year.^10,11

• National Institute for Health and Clinical Excellence (NICE) guidance states that women with a previous Caesarean section can be offered induction of labour but they should be aware that the risk of uterine rupture is increased (to 80 per 10,000 using non-prostaglandin agents and to 240 per 10,000 with prostaglandins).^8,11
• Pregnant women with previous Caesarean section and vaginal births have a higher likelihood of a vaginal birth compared with women who have only a previous Caesarean delivery.¹⁰
• Research supports a maximum oxytocin dose of 20 mU/min in trials of labour, to avoid an unacceptably high (4x greater) risk of uterine rupture.¹²
• There is insufficient evidence to support denying women with 2 or more Caesarean sections a trial of labour.^13,14

Document references

1. Kieser KE, Baskett TF; A 10-year population-based study of uterine rupture. Obstet Gynecol. 2002 Oct;100(4):749-53. [abstract]
2. Zwart JJ, Richters JM, Ory F, et al; Severe maternal morbidity during pregnancy, delivery and puerperium in the Netherlands: a nationwide population-based study of 371,000 pregnancies. BJOG. 2008 Jun;115(7):842-50. [abstract]
3. Toppenberg KS, Block WA Jr; Uterine rupture: what family physicians need to know. Am Fam Physician. 2002 Sep 1;66(5):823-8. [abstract]
4. Leung AS, Leung EK, Paul RH; Uterine rupture after previous cesarean delivery: maternal and fetal consequences. Am J Obstet Gynecol. 1993 Oct;169(4):945-50. [abstract]
5. Landon MB, Hauth JC, Leveno KJ, et al; Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9. Epub 2004 Dec 14. [abstract]
6. Bujold E, Gauthier RJ; Neonatal morbidity associated with uterine rupture: what are the risk factors? Am J Obstet Gynecol. 2002 Feb;186(2):311-4. [abstract]
7. Grobman WA, Lai Y, Landon MB, et al; Prediction of uterine rupture associated with attempted vaginal birth after cesarean delivery. Am J Obstet Gynecol. 2008 Apr 23;. [abstract]
8. Caesarean section, NICE Clinical Guideline (2004)
9. Guise JM, Eden K, Emeis C, et al; Vaginal birth after cesarean: new insights. Evid Rep Technol Assess (Full Rep). 2010 Mar;(191):1-397. [abstract]
10. Smith GC, Pell JP, Pasupathy D, et al; Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study. BMJ. 2004 Aug 14;329(7462):375. Epub 2004 Jul 19. [abstract]
11. Intrapartum care, NICE Clinical Guideline (2007)
12. Cahill AG, Waterman BM, Stamilio DM, et al; Higher maximum doses of oxytocin are associated with an unacceptably high risk for uterine rupture in patients attempting vaginal birth after cesarean delivery. Am J Obstet Gynecol. 2008 May 1;. [abstract]
13. Emembolu JO; Vaginal delivery after two or more previous caesarean sections: is trial of labour contraindicated? J Obstet Gynaecol. 1998 Jan;18(1):20-4. [abstract]
14. Spaans WA, van der Vliet LM, Roell-Schorer EA, et al; Trial of labour after two or three previous caesarean sections. Eur J Obstet Gynecol Reprod Biol. 2003 Sep 10;110(1):16-9. [abstract]

Acknowledgements