Introduction
Uterine rupture in pregnancy is a rare and serious condition. It can result in catastrophic outcomes for both the mother, such as haemorrhagic shock, the need of peripartum hysterectomy and death; and the child, such as hypoxic ischaemic encephalopathy, permanent brain injury and even death1. In general, the rate of uterine rupture ranges from 1 in 1235-4366 pregnancies2, being that the majority occurs in uterus with a previous scar. The cases reported in unscarred uterus are much lower, with incidence being reported as 1 in 16,840 - 19,765, where the prognosis is even worse3,4. Other risk factors associated with this condition are malpresentation, second-stage dystocia, sequential labour induction with prostaglandins/oxytocin and augmentation of labour with oxytocin5,6.
Cases with insidious onset of disease and lack of specific symptoms lead to a misdiagnosis or a delayed diagnosis. Nevertheless, a quick and accurate diagnosis followed by definitive treatment plays a critical role in lowering morbidity and mortality.
Here, we are reporting an unusual case of spontaneous posterior wall rupture in a woman without any apparent risk factors.
Case Report
We present a case of a 34-year-old, gravida 2 para 1, at 40+2 weeks, admitted in our centre in spontaneous labour. Her medical history was unremarkable and her obstetric history included a regular pregnancy with spontaneous vaginal (forceps) delivery 4 years before. Routine third trimester ultrasound revealed a fetus in P50 of growth, and all other exams demonstrated a normal pregnancy course.
At arrival, mother vital signs were stable and the cardiotocograph performed during labour showed a normal fetal heart rate. No labour augmentation with oxytocin was used. An assisted vaginal delivery with outlet forceps was performed due to mother exhaustion, and a 3096 g baby was born with an Apgar score of 9/10 at 1st and 5th min, respectively. An episiotomy was done and then repaired.
Thirty minutes after birth, the mother developed signs of hypovolemic shock: refractary hypotension and a drop in hemoglobin from 11 g/dL to 7 g/dL. An abdo-mino-pelvic ultrasound was performed showing an empty uterus and no signs of hemoperitoneum. Birth canal injuries were ruled out. The patient was placed in Trendlenburg position and started a 2 U red blood cell transfusion with a Ringer’s Lactacte solution perfusion.
Four hours later, because of the patient’s sustained condition (hypotension, same level of hemoglobin and beginning of nausea, dyspnea and abdominal pain) another abdomino-pelvic ultrasound was done where a massive hemoperitoneum was found in the right hypochondrium. Suspecting of an abdominal organ injury, an urgent abdominal laparotomy was performed and revealed a massive hemoperitoneum caused by a complete posterior uterine wall rupture which was actively bleeding. The wall defect, with 6cm, that extend from the midline throughout the whole right broad ligament was repaired with a 2-layer seromuscular suture with uninterrupted stitches.
The patient’s postoperative course was regular, and she was discharged 8 days after intervention.
Discussion
Uterine rupture occurs in less than 1% of pregnancies with a previously scarred uterus, being the incidence in unscarred uterus even lower. (3
A wide range of risk factors involves labour induction, with particular attention to the use of oxytocin and/or prostaglandins and augmentation of labour with oxytocin6,7. Connective tissue diseases like Ehlers-Danlos syndrome, chronic steroid use, cocaine abuse1, grand multiparity leading to weakened muscle fibres, instrumental delivery and congenital malformations are all predisposing factors for uterine rupture8.
The diagnosis can be challenging due to the vast clinical presentation that may vary from nonspecific signs and symptoms like abdominal pain, hypovolemia and tachycardia9 to more specific but non pathognomonic signs like fetal compromise in CTG, changes in fetal presentation, loss of uterine contour or vaginal bleeding1. Therefore, it is important to maintain a high index of suspicion, mainly in the absence of the major risk factor - uterine scar - in order to avoid delayed diagnosis and intervention10.
The event can occur antepartum, intrapartum and postpartum. Antepartum, towards an abdominal pain, that is the most common clinical symptom11, an exploratory laparotomy may be performed to repair the defect and continue the pregnancy12.
Postpartum, uterine rupture may present with abdominal pain, postpartum hemorrhage and unexplained clinical shock. A delayed diagnosis towards an unexplained clinical shock may occur in the absence of risk factors10.
Iqbal Al‐Zirqi, et al. (13 argues that the majority of ruptures occur beside the lower uterine segment in unscarred uterus and within the lower uterine segment in scarred ones. Ruptures beside the lower segment occurred mostly in the anterior and posterior corpus and within the lateral side, involving the broad ligament4. Ruptures in the fundus may have a delayed dia-gnosis because blood collects in the intra-peritoneal cavity. Another study also found out that cervical involvement was significantly more prevalent in the rupture of an unscarred uterus5. Ruptures in unscarred uterus also carry more catastrophic maternal outcome, including the need of hysterectomy13.
Uterine rupture demands urgent resuscitation and exploratory laparotomy where the importance of immediate senior involvement and teamwork cannot be despised. The goal of the intervention is to stop the hemorrhage, repair the anatomic damage, and reduce morbidity. The decision of surgical repair or a hysterectomy must be based on several factors such as the size of the uterine defects, the degree of bleeding, patient age, parity and comorbidities.
The risk of rupture in a future pregnancy is related to the site of the rupture - if it is confined to lower segment, the risk is 6% while if it involves the upper segment it increases to 32%1. For women who had a previous uterine rupture or dehiscence, it is recommended to give birth by repeating a caesarean section prior to the onset of labour or immediately at the onset of spontaneous preterm labour14. To minimise unnecessary interventions, resulting in the delivery of extremely premature infants, it is cardinal to recognise risk factors and signs of uterine rupture.
We report this case in order to call attention to the fact that, despite being very rare in women without risk factors, a primary rupture in an unscarred uterus may occur. In women presenting severe abdominal pain and hemodynamic instability, uterine rupture should be considered, as a differential diagnosis. An increased awareness to this entity, a life-threatening condition, may allow earlier diagnosis and prompt treatment resulting in optimal outcomes and no severe complications.