Uterine rupture is a catastrophic obstetric complication that contributes to significant maternal and fetal adverse outcomes including death, especially in developing countries [4, 21]. The main reason is prolonged delays in receiving appropriate care and limited clinical resources including personnel, supplies and equipment [21]. Several studies in Sub-Saharan Africa have reported significant contribution of uterine rupture to overall maternal deaths ranging from 6.6% to around 18% and perinatal case fatality rate of around 74% to 92% [1, 4, 13, 22]. The gravity of this complication was also seen in our study especially for perinatal deaths and maternal morbidity.
Incidence of uterine rupture
In this study, the incidence of uterine rupture is higher than in developed countries, which is less than 0.1% (1 case per 1,000) according to a WHO systematic review in 2005 [4]. However, our findings are in keeping with findings of the systematic review which showed that in low-income countries, uterine rupture was more prevalent compared to developed countries [4]. This difference between developed countries and low-income countries, may be due to the differences in quality of obstetric care and other social-cultural and economic factors such as healthcare seeking behavior in a given society, infrastructural constraints, personnel, equipment and supplies in health facilities. However, the incidence in our study is lower than that reported in most other African countries (0.5% - 5%) but similar to a study done at MNH, Tanzania. This may partly be related to free provision of antenatal care (ANC) services in Tanzania in which ANC attendance is approximately 98% in which awareness towards possible danger signs and complication readiness is made [23]. The association between incidence of uterine rupture and low attendance or utilization of antenatal care services has been reported in studies done in several parts of Africa and many authors stressed the potential benefit of regular antenatal care attendance in reducing the incidence of uterine rupture [11, 17, 24-27].
Maternal outcomes
In our study, one fifth of the cases developed sepsis which led to prolonged hospital stay (stay of more than 7 days) in 13 of the 14 cases. Likewise, sepsis was associated with a 9-fold increased risk of re-laparotomy (OR=9.18, CI 2.1 - 39.9 and p-value of 0.003). At BMC most patients post caesarean section are routinely discharged on the 3rd day although a few do stay for 7 days and post caesarean section sepsis was shown to be 11%, almost half that reported in our study [28]. Therefore, ruptured uterus means much more morbidity and cost to the patient as well as the hospital and the community. Our findings are almost similar to studies done in MNH-Tanzania and Sudan where sepsis developed in 18% and 17% of the cases respectively [1, 29]. However, in some other studies sepsis was less common than in our study, 10% - 13% in Nigeria and Northwest Ethiopia while it was higher in studies done in Uganda, 34% - 40% [7, 12, 15]. This variability may be due to differences in patient presentations and co-morbidities, use of prophylactic antibiotics, adherence to infection-prevention control, experience of surgeons performing the procedure and methodological differences between studies [21, 28].
Eight cases (12%) developed VVF in this study compared to 6% in a study done at MNH, Tanzania and 2% - 5% in studies done elsewhere [1, 7, 30, 31]. Ten cases (15%) in this study required re-laparotomy, six were due to peritonitis and/or burst abdomen and four were due to continued internal bleeding. Slightly different findings were reported in studies done in Niger delta in Nigeria (10.3%) and in a tertiary care center in Turkey (11.5%) [26, 32]. The different rates of these complications in different studies may probably be related to patient presentation, site and extent of rupture and degree of distortion of the pelvic anatomy, surgical intervention, experience of the surgeon and presence of risk factors for development of sepsis or delay of wound healing like anemia or prolonged obstructed labor. As seen in our study, most of those who developed either VVF or required re-laparotomy presented with obstructed labor and most of them underwent hysterectomy and were operated by residents /registrars than obstetricians. However, obstructed labor was the only factor that had statistically significant association with VVF development in patients studied and none of the aforementioned factors showed significant statistical association with increased re-laparotomy risk in our study although this could be due to small sample size and low rates of these complications.
In this study there was one maternal death. This is equivalent to case fatality rate of 1.5% similar to a study done in UK which reported a case fatality rate of 1.3% [33]. This is contrary to other studies done in Africa where maternal case fatality rates were reported to be high, 6% - 16% [1, 3, 12, 34]. Several factors have been shown to affect maternal outcomes in cases of uterine rupture. These include; patient status on presentation, prompt diagnosis, adequate resuscitation, timely surgical intervention, availability of blood for transfusion as well as whether or not the rupture occurred in scarred uterus [24, 35-37]. The low maternal case fatality rate in our study may probably be due a higher proportion of ruptures in patients with previous uterine scar than unscarred uteri [37]. Moreover, most patients (84%) were operated within less than 1 hour of diagnosis of uterine rupture or impending uterine rupture, as it was shown in a study done in Ile-Ife, Nigeria that delay of 1hr or more was associated with increased maternal case fatality rates [36]. Likewise, adequate resuscitation with intravenous fluids was done and blood for transfusion was available to all patients who needed it intraoperatively and postoperatively. Only 12% of patients in this study presented with hypovolemic shock which was shown to be associated with maternal death in patients with uterine rupture in a study done in Northwest Ethiopia [24]. However, all were successfully resuscitated with intravenous fluids and intraoperative blood transfusion and they all survived.
Surgical intervention
In this study, approximately two thirds of the patients underwent hysterectomy. Majority were relatively young aged below 35 years which may have a significant negative psychosocial impact on these patients due to, not only, loss of fertility potential but also loss of menstruation [21]. However, subtotal hysterectomy was shown, in a review by Thakur et al in 2001, to be associated with less maternal morbidity such as sepsis and need for re-laparotomy and also less mortality than uterine repair, which might have influenced the decision by some surgeons at BMC [38]. However, several other factors might have influenced the type of surgical intervention such as the location and extent of the uterine tear, surgeon experience and hemodynamic stability of the patient [11]. As concluded in a review by Walsh et al in 2007, there is insufficient evidence to recommend either hysterectomy or repair of the uterus as standard surgical management of uterine rupture [39]. Expectedly, studies done elsewhere, show a great variability in surgical intervention, others reporting higher hysterectomy rates while others report higher uterine repair rates [1, 7, 26, 34, 40, 41]. Although uterine repair without BTL carries a significant risk of subsequent uterine rupture, excellent pregnancy outcomes can be achieved with appropriate care including strict delivery by caesarean section (elective or immediate in case premature labor starts) [42-44]. It is therefore an option that should be considered whenever possible in patients who desire future pregnancies [43]. In our study, repair of the uterus without BTL was done in approx. one thirds of patients which is similar to studies done elsewhere [7, 26, 45]. Some other studies reported even a higher proportion of patients, 56 - 70% underwent uterine repair without BTL [3, 29].
Fetal outcomes
Adverse fetal outcomes are also a common finding in patients with ruptured uterus. However, there is a great variability in the rates of these outcomes such as perinatal deaths in different studies. As shown in this study, perinatal case fatality rate was high compared to developed countries where reported perinatal case fatality rate is 5% to 14% [5, 13, 22]. However, our findings were lower than in studies done elsewhere in Africa where perinatal case fatality rate ranged from 80% to 100% [2, 7, 33, 34]. Differences in patient presentation (early/late presentation), quality of care at health facilities including prompt diagnosis and surgical intervention, prompt referrals, newborn resuscitation, proper management of babies with birth asphyxia including presence of well-equipped and functioning neonatal intensive care units may partly explain the variability observed [1, 21]. At BMC, there is a well-functioning neonatal intensive care unit which is relatively adequately equipped and staffed, however most of the babies in this study were stillbirth which could therefore not change the perinatal case fatality rate. The high still-birth rate may be a proxy to severity of the disruption of fetal-placental unit at diagnosis or intervention in the cases in this study [21]. Several studies have reported that continuous electronic fetal monitoring in women on trial of scar may improve both maternal and fetal outcomes by detecting early signs of fetal compromise such as bradycardia, repetitive variable decelerations and/or late decelerations associated with uterine rupture, hence prompting early intervention. Most common features detected are [46, 47]. Absence of cardiotocography (CTGs) at our facility for monitoring of labor in high risk patients may have contributed to delays in diagnosis of fetal compromise and the hence the observed high perinatal case fatality rate.
Risk factors for uterine rupture
In this study, the leading risk factor for uterine rupture seen was history of previous caesarean section followed by obstructed labor, use of oxytocin for induction or augmentation of labor and grand multiparity. As in other study, a study done at Lagos university teaching hospital in Nigeria, reported previous uterine scar as the leading risk factor for uterine rupture followed by obstructed labor and injudicious use of oxytocin [2]. These risk factors for uterine rupture had been reported at varying proportions in different studies [1, 17, 34, 48]. However, according to a systematic review by WHO and a review of uterine rupture in resource-poor settings by Berhe et al in 2014, the main risk factor for uterine rupture in developing countries was prolonged obstructed labor [4, 21]. The increasing rate of caesarean section may have contributed to increased proportion of uterine scar as a leading risk factor among patients with uterine rupture as seen in our study. Example in Tanzania, caesarean section rate has increased from 3% in 2004/2005 to 6% in 2015/2016 [23].
There were few limitations to this study which included missing files and incomprehensive documentation in the available files. For example, in most files there was no documentation of the indication for prior caesarean section, no information on other uterine surgeries such as myomectomy or uterine evacuations which may contribute to increased risk for uterine rupture. Also, physical examination findings were not well documented in most files, information about birthweight of the babies was missing in some files, operative notes were very deficient in most files and estimated blood loss was rarely documented in most of the files. Moreover, the referral letters in the referred patients lacked a lot of necessary information including duration of labor and specific interventions done to the patients before the referral. Finally, the study was able to determine only short term fetomaternal outcomes based on the recorded information in patients’ case files only, long term psychosocial impact could not be assessed.