Uterine inversion is defined as a protrusion of the uterus into the endometrial cavity and potentially through the vaginal orifice that can occur in the puerperal and non-puerperal period. The causes and management of puerperal and non-puerperal uterine inversion are different. It can be acute, subacute or chronic and may occur with either vaginal or Caesarean delivery. In this article, we focus on uterine inversion occurring after the third stage of a vaginal delivery (i.e. puerperal uterine inversion). Puerperal uterine inversion can progress to bleeding from areas of placental separation because of the inability of the uterus to contract normally, leading to postpartum haemorrhage (PPH) if not recognised and managed early.
Classification
The degree of uterine inversion may be classified into four grades based upon the extent of uterine extension into the cervical or vaginal orifice.1
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(i)
First degree: corpus or wall of uterus extends into the cervix
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(ii)
Second degree: corpus of uterus passes through the cervical ring but does not reach the perineum
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(iii)
Third degree: fundus of uterus extends to the perineum
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(iv)
Fourth degree: uterus and vagina invert past the perineum
Incidence
Uterine inversion is a rare but potentially fatal complication that has an incidence of between 1 in 3500 to 1 in 20,000 vaginal deliveries worldwide.2,3 It is likely that this range in reported incidence results from variation in the characteristics of the patients studied and the management of the third stage of labour. In the USA between 2004 and 2013, 37.7% of patients who had uterine inversion went on to have PPH as well; 22.4% of patients who had PPH needed blood transfusion; and one death occurred.4 Similarly, in the UK, the MMBRACE-UK (Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK) publication in 2020 reported one death between 2006 and 2008 and two deaths between 2016 and 2018.5
Predisposition and risk factors
The pathogenesis of uterine inversion is not clearly understood, but multiple factors appear to be associated (Table 1).1,4 Conditions that weaken the integrity of the uterine wall increase the likelihood of uterine inversion, including congenital disorders of the uterine wall or cervix; connective tissue disorders such as Marfan syndrome and Ehlers Danlos disorder; uterine structural anomalies; and tumours.1,6 Problems of abnormal placentation, such as the presence of fundal or morbidly adherent placentation, and prolonged labour may increase the possibility of uterine inversion, the latter owing to uterine muscle fatigue.3,4,6 In an observational cohort study, severe pre-eclampsia was found to be a significant risk factor, but not fetal macrosomia or multiparity, which have been related to uterine inversion in other studies.4 The use of Crede's manoeuvre (where pressure is applied on the uterine fundus to aid placental separation) and excessive traction of the umbilical cord, has been related to uterine inversion. There is limited evidence to suggest an increased risk of recurrence of uterine inversion subsequent to previous uterine inversion.7
Table 1.
| Risk factors | |
|---|---|
| Antepartum MATERNAL CONDITIONS
|
Intrapartum IATROGENIC
|
Clinical presentation
The patient is most likely to complain of severe lower abdominal pain during and after the third stage of labour. Profound bradycardia and hypotension may occur, and the degree of hypotension is normally disproportionate to the extent of blood loss. Significant pelvic parasympathetic with vagal stimulation, particularly when second-, third- and fourth-degree uterine inversions occur, is responsible for the manifestation of severe hypovolaemic and neurogenic shock.6,7 This should alert the clinician to consider uterine inversion. Vaginal bleeding may be present and is secondary to inadequate contraction of the uterine fundus and stretching of the inverted endometrium, exacerbating bleeding from any areas of placental separation. Further, uterine inversion should be considered if a decrease in uterine fundal height is found without placental delivery or the uterine fundus is not palpable in the abdomen, with or without pelvic examination suggesting the presence of a mass in the vagina or introitus.6
Goals of management
It is essential that the anaesthetist and the rest of the multidisciplinary team are prepared to transfer the patient to the operating theatre. The goals are:
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(i)
Replacement of uterus to correct anatomical position
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(ii)
Management of initial shock
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(iii)
Management of PPH
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(iv)
Management of pain
Replacement of uterus
The definitive management of uterine inversion is the replacement of the uterus into its correct anatomical position as soon as possible. Contraction of the lower uterine segment and cervix, leading to a constriction ring, and oedema of the uterus can develop if it is not quickly repositioned and result in progressive difficulty in further attempts at replacement.7 Immediate assistance must be called for. Uterotonic agents and attempts to remove the placenta should be stopped to increase uterine relaxation and limit blood loss, respectively. Manual replacement of the uterus involves placement of a hand inside the vagina and pushing the uterine fundus along the long axis of the vagina towards the umbilicus. It may require tocolytic medications such as glyceryl trinitrate, terbutaline, magnesium sulfate and potentially volatile inhalational agents to be given.3,6,8,9
If the patient is haemodynamically stable, then manual replacement of the uterus may be reattempted. In one case series, manual replacement of the uterus was unsuccessful in one third of patients.3,10 Should the patient remain haemodynamically stable, hydrostatic repositioning with the O'Sullivan procedure can be considered.11 In this technique, the patient is placed in the lithotomy position, 5–6 L warm sterile saline is infused into the upper vagina to distend the fornices and open the cervical ring, and the vaginal introitus is sealed with a closed hand or the use of a ventouse cup.11
If these measures fail, or the patient is haemodynamically unstable, prompt replacement of the uterus is required through surgical intervention in the operating theatre. If an existing epidural catheter was used for labour analgesia, this can be extended to provide surgical anaesthesia. However, general anaesthesia with the use of inhalational volatile agents may be preferred to stimulate relaxation of the uterus3, 6, 8, 9 (Fig. 1).
Fig 1.
Cognitive aid for the recommended management of uterine inversion.3,6,8,9 GTN, glyceryl trinitrate; MgSO4, magnesium sulfate; SL, sublingual.
Surgical intervention is performed via laparotomy using Haultain's procedure, a posterior uterine incision to release the constriction ring and facilitate manual reduction; or Huntington's procedure, the application of gentle upward traction via clamps placed on the round ligaments of the uterus.
Management of initial shock
Anaesthetists must ensure the patient is monitored adequately with ventilatory frequency, oxygen saturation, ECG, continuous arterial blood pressure if possible and urine output. Initial resuscitation should focus on the management of neurogenic shock, hypovolaemic shock, or both. Large-bore i.v. cannulae are recommended for resuscitation and oxygenation should be maintained. Management of significant bradycardia with atropine may be needed to achieve, maintain, or both haemodynamic stability. Vasopressor drugs may be required to manage significant hypotension. Such resuscitation measures should proceed concomitantly with uterine replacement. Provisions should be made for blood products with cross-matching of blood, urgent coagulation and full blood count measurements. Point-of-care testing should be considered if it is available.
Management of PPH
The multidisciplinary team should anticipate the possibility of uterine atony and subsequent PPH, and hence prepare uterotonic agents such as oxytocin, ergometrine, carboprost and misoprostol to be given once the uterus has been replaced. This is to support uterine contraction and minimise further blood loss.12 Blood tests such as full blood count and coagulation, cross matching of blood and relevant point-of-care tests should be performed. The use of tranexamic acid may be beneficial. Management of major obstetric haemorrhage has been discussed in a recent article in BJA Education.13
Management of pain
Pain can be severe in the presence of uterine inversion and this can often be overlooked in the presence of haemodynamic instability. Alfentanil 100–250 μg i.v. given in an incremental manner may be beneficial, especially in the patient without pre-existing epidural analgesia and in the interim before regional or general anaesthesia is performed. In the patient with a pre-existing labour epidural, an initial epidural bolus of local anaesthetic and opioid such as lidocaine 2% with adrenaline (epinephrine) 1:200,000 and fentanyl 25–50 μg may be given. However, anaesthetists must be mindful of the potential of worsening hypotension and therefore vasopressors should be considered concomitantly.
Key action points to consider
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(i)
Early recognition of uterine inversion, especially when shock is disproportionate to blood loss.
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(ii)
Urgent replacement of the uterus into correct anatomical position and concurrent resuscitation.
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(iii)
Discontinuation of uterotonic medications until replacement of the uterus and potential use of tocolytic medications to relax and support replacement of uterus.
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(iv)
Anticipation of and preparation for PPH with uterotonic agents and blood products.
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(v)
Possible transfer to surgical theatre and extension of epidural anaesthesia or induction of general anaesthesia with volatile inhalational agents.
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(vi)
Management of acute pain with either i.v. fast-acting opioids or regional anaesthesia.
Conclusions
Puerperal uterine inversion is a rare but potentially life-threatening complication of vaginal delivery. It is important to promptly recognise and manage uterine inversion to avoid significant maternal morbidity and mortality. The anaesthetist should anticipate and manage significant haemodynamic instability and PPH. Communication and teamwork among the multidisciplinary team is vital to facilitate the optimal management of uterine inversion.
Declaration of interests
None declared.
Biographies
Suji Pararajasingam BSc (Hons) FRCA is a specialty registrar in anaesthesia at Guys and St Thomas' NHS Trust who has specialist interests in obstetric anaesthesia and maternal cardiac health.
Lawrence Tsen MD is an associate professor in anaesthesia at Harvard Medical School and the Brigham and Women's Hospital. He is the director of anesthesia for the Center for Reproductive Medicine, and recently served as associate director for professionalism and peer support.
Desire Onwochei BSc (Hons) FRCA MSc is a consultant anaesthetist at Guy's & St Thomas' NHS Foundation Trust who completed fellowships and research in regional anaesthesia, obstetrics and airway management. She has a keen interest in the application of regional anaesthesia in obstetrics.
Matrix codes: 1D02, 2B05, 3B00
References
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