The main cause of MOH in our study was placental abruption. The majority of these women suffered from hypertensive disease of pregnancy and lost their child. Other frequent causes of MOH were complications during or after CS and uterine atony. It is remarkable that only CS was associated with poor maternal outcome. Moreover, uterine rupture was seldom encountered in the overall MNM group.
The reported incidence of MOH is comparable to prior published incidence rates in Pretoria, South Africa in 1998 (3 per 1000 births) and 2001 (2.8 per 1000 births).20, 21 Incidence rates in high-income countries are reported to be 2.3 per 1000 births (Ireland in 2011).22 The WHO Multicountry Survey on Maternal and New-born Health reported incidence rates for postpartum haemorrhage of 2.9, 1.4 and 2.0 per 1000 births for low, medium and high Human Development Index countries in 2012.5 Yet, this survey audited severe maternal outcome (MNM and MD) due to postpartum haemorrhage only, whereas our study included antepartum and intrapartum haemorrhage as well. The incidence of postpartum haemorrhage in our study was 1.9 per 1000 births, comparable to the medium to high Human Development Index countries in the WHO survey. In general, the comparison of incidence rates of obstetric haemorrhage remains difficult, because definitions vary widely in the literature. On the other hand, the case fatality rate of MOH was low (0.9%) and is consistent with the literature.5, 9
The finding of placental abruption as the main cause of MOH in our population cannot easily be compared with other populations since most studies report antepartum haemorrhage and postpartum haemorrhage separately. The fact that uterine atony is not the most frequent cause for MOH is probably also because our study combines MOH before, during and after birth.9, 23 This underlines the importance of including ante- and intrapartum bleeding in studies of MOH, rather than limiting their scope to include postpartum haemorrhage only.
Hypertensive disorders of pregnancy, placental abruption and preterm labour are pathophysiologically related with early ischemic placental disease.21, 24
The fact that stillbirths occurred in 95 % of women with abruption was not unexpected, given that the large majority presented already in shock or with symptoms of disseminated intravascular coagulation. Despite knowledge that appropriate management is to deliver stillbirths vaginally, in daily practice this is not always possible, due to acute maternal compromise requiring surgical intervention. In this study, we reported a relatively high number of CS in cases of stillbirth. Indications were maternal condition too poor for induction of labour (3/7), ≥2 previous CS , (1/7, relative contra-indication to induce), failed induction (2/7) or ruptured uterus (1/7).
The high number of complications during and after CS can be related to the risk factors of the women in this population. The high percentage of women with obesity (26.9% BMI ≥30) and hypertensive disorders may complicate CS. Secondly, lack of skilled doctors can be associated with poor maternal outcome after CS.11, 25, 26 The majority of women with MNM had low-risk pregnancies and were referred from level 1 hospitals with a high patient burden, mainly managed by medical officers and only one or two obstetricians present. Further audit may give more insight into the quality of care in this setting.
With regard to interventions in the management of MOH, low rates of intrauterine balloon tamponade, and administration of tranexamic acid are notable. This can be explained by the fact that, in 2014, tranexamic acid was not yet included in the local guidelines. The Bakri balloon for intrauterine tamponade is a relatively expensive device and therefore rarely utilised at TBH. An alternative and more affordable device, the Ellavi balloon, was developed in South Africa, but only introduced in 2016.27
Even though our study suggests that the local protocol for management of MOH was followed, detailed information - e.g., timing, availability, and quality of the interventions and training of staff – will have to be studied in more depth in order to identify opportunities to improve management of MOH.
Because of the increasing trend of MOH in the Western Cape province, recommendations from the National Committee on Confidential Enquiries into Maternal Deaths to implement guidelines that prevent MOH, develop protocols for management of postpartum haemorrhage with tranexamic acid and balloon tamponade and practicing emergency drills, should be prioritised. .11 Antenatal care and appropriate blood pressure control for hypertensive disease are, however, just as important to prevent MOH and abruptions.
There is no worldwide consensus on blood transfusion protocols, due to a lack of strong evidence, which is a result of discrepancy in definitions, resources and only few available randomized controlled trials.19, 28 At TBH, the local severe haemorrhage protocol recommends that, if bleeding is not controlled after the administration of 4 units of RBCs, to infuse blood products in a ratio of 1 RBC: 1 Fresh Frozen Plasma: 1 platelets. However, our data does not reflect this recommendation meaning more individualized care was performed in practice.
We importantly adhered strictly to the criterion of ≥5 RBCs for inclusion as MNM. Nonetheless, we also separately assessed massive blood transfusion since this assessment enabled comparisons with studies done in other countries. The incidence of massive transfusion was 40 per 100.000 births and is within the range of the incidence reported for the United Kingdom between 2012 and 2013 (23 per 100.000 births) and the Netherlands between 2011 and 2012 (65 per 100.000 births),17, 18 using the same definition for massive blood transfusion.
The strength of this study is that nearly all women with MOH from the Metro East region were included in our database as a result of a well-organized referral system. Under reportage was investigated and, in three months, only three women with MNM were missed in the level 1 hospitals, meaning 12 were missed in one year so that only 3% of cases of MNM were underreported, . Hence, these data are considered population-based at district level. This emphasizes the need and value of a national maternal health care and perinatal data registry, which is not presently available in South Africa. Limitations of the study are that, despite our efforts of daily assessment, either incomplete documentation or inadequate data extraction from handwritten medical files could have led to information bias or non-differential misclassification. For instance, the history of hypertensive disease in pregnancy or previous pregnancies was difficult to trace and the already high prevalence of hypertensive disease of pregnancy during placental abruption can thus still be an underestimation. Although the cause of haemorrhage is likely to be multifactorial, it often involves uterine atony. Since we only documented the primary cause of haemorrhage, there might be an underestimation of the incidence of uterine atony as well.