Espresso: Uterine Rupture

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What is uterine rupture? 

  • Definition

    • Spontaneous tearing of the uterine muscles which can lead to expulsion of the fetus into the peritoneal cavity

    • In the literature, uterine rupture can also incorporate less catastrophic phenomena, like uterine window or asymptomatic scar dehiscence without expulsion of the fetus

    • Focus today: intrapartum uterine rupture.

    • The true incidence of uterine rupture across all populations in pregnancy is likely very low.

      • With no history of surgery, the risk is 1/8000-17,000 deliveries 

    • With one prior low transverse cesarean, the incidence has been reported to be between 0.2-1.5%, though usually quoted as <1% 

    • With two prior low transverse cesareans, the incidence is reported to be between 0.8-3.9%, usually quoted as just over 1% 

    • However, there are things that can modify this risk: 

      • History of prior successful VBAC → reduce the risk of rupture from 1.1% to 0.2% 

    • In other types of incisions such as T-incisions and classical incisions, the rate of rupture can be as high as 4-9%

  • What are some other risk factors? 

    • By far, the biggest one is previous uterine surgery,

    • Other risk factors: 

      • Uterine scar presence

      • Uterine anomalies

      • Prior invasive molar pregnancy

      • History of placenta accreta spectrum

      • Malpresentation

      • Fetal anomaly

      • Obstructed labor

      • Induction of labor with use of prostaglandins

        • These other risk factors are much less significant than prior uterine surgery/presence of scar  

How do I recognize uterine rupture?

  • Again — only be discussing uterine rupture in labor 

    • There are a few studies looking at thinning of the myometrium on ultrasound, but this is controversial.

    • It is much more likely that you will encounter uterine rupture at time of labor and birth than during other times 

  • Diagnosis

    • High index of suspicion - know your patient’s risk factors and be on the lookout for uterine rupture given how catastrophic it can be for both maternal and fetal wellbeing 

    • Some of the classical signs: 

      • Sudden, tearing uterine pain

      • Vaginal hemorrhage

      • Cessation of contractions 

      • Destationing of the fetal head 

    • However, these classical signs are actually not necessarily reliable and not always present! 

    • The most reliable presenting clinical symptom is actually fetal distress 

      • One study of 99 patients with uterine rupture showed: 

        • Only 13 patients reported pain and 11 had vaginal bleeding 

        • However, bradycardia or signs of fetal distress (decelerations) were present in the majority.

    • Ultrasound examination 

      • Not necessarily reliable and if you are truly suspicious of uterine rupture, this should prompt immediate delivery 

  • Why do we need to diagnose uterine rupture promptly? 

    • Maternal complications

      • Maternal circulatory system delivers 500 cc of blood to the uterus every minute 

      • Uterine rupture increases the risk of hemorrhage, with studies showing that about 50% of cases result in EBL of 2000cc or greater 

      • This can lead to need for blood transfusion, and in more dire circumstances, hysterectomy  

    • Fetal complications 

      • Depends on how quickly the neonate is delivered after recognition of uterine rupture 

      • One study showed a neonatal mortality rate of 2.6%, and increases to 6% if uterine rupture occurs outside of the hospital

        • Older literature report rates as high as 13%  

      • Many neonates will require resuscitation and admission to the NICU 

Management

  • The best form of management is prevention or setting expectations - ie. counseling 

    • All patients who desires a trial of labor after cesarean section should be counseled about the risks and benefits of TOLAC 

    • Patients should deliver at a location where labor and delivery staff, anesthesia staff, and neonatal staff are available 24 hours in order to facilitate prompt delivery if needed. 

    • Patients who are at high risk of uterine rupture (ie. classical cesarean, T-incision, prior uterine rupture, >2 cesarean sections, history of prior fundal surgery) should be counseled against TOLAC 

    • We did a whole episode on TOLAC counseling back in 2019, so check it out here: https://creogsovercoffee.com/notes/2019/9/22/trial-of-labor

      • Note that the VBAC calculator we included in those notes is outdated! 

    • There is a new VBAC calculator available that does not include race as a predictor: https://mfmunetwork.bsc.gwu.edu/web/mfmunetwork/vaginal-birth-after-cesarean-calculator

  • What if it happens? The answer is prompt delivery via cesarean delivery 

    • Urgent delivery - as quickly as possible, but within 30 minutes generally 

    • Patient can be under general anesthesia or if they already have working regional anesthesia, this can also be used 

    • Cesarean delivery should be performed, and if there is a uterine rupture, the neonate can often be delivered via the area of rupture without creating a new hysterotomy 

      • However, if there is just a uterine window, a hysterotomy may be needed 

    • Once the neonate is delivered, pediatrics should be there immediately to facilitate resuscitation 

    • If uterine rupture is confirmed, a full exam of the uterus should be done to assess for other injury 

      • Ie. bladder injury, broad ligament hematoma 

    • If possible, the area of rupture should be repaired 

    • However, if it is not possible to repair the rupture due to significant damage, patient is not stable, or significant hemorrhage, then the next step should be hysterectomy 

  • Follow-up 

    • Debriefing - this should occur with the team who was present for uterine rupture 

    • But also, should discuss with your patient when they are at a place when they can discuss what happened 

    • Counsel patient that if they desire future pregnancy, TOLAC should not be attempted due to increased risk of repeat rupture