Obstructed Labour and Uterine Rupture in the Global Burden of Disease 2021 Study: A Metric Requiring Nuanced Interpretation

After 5 days of obstructed labour, Abebech successfully delivered a stillborn baby in Ethiopia [1]. She then endured 27 years of profound discomfort, embarrassment and social stigmatisation due to chronic urine incontinence from an obstetric fistula as a direct consequence of her obstructed labour. Abebech's story exemplifies the plight of millions of women and birthing people globally who endure serious, lifelong complications from obstructed labour. These complications, including uterine rupture, foetal death, haemorrhage and hysterectomy [2], not only pose significant health risks, but also negatively impact the quality of life, leading to social isolation, emotional trauma and financial hardship [3]. The global health burden of obstructed labour is disproportionately shouldered by individuals like Abebech, who live in low-and-middle-income countries that are also grappling with poor maternal and neonatal health outcomes. While obstructed labour has a lower risk of immediate mortality than some other obstetrical emergencies [4], it remains an understudied, but critical area of maternal health. High-quality epidemiologic research is needed to accurately characterise the incidence of obstructed labour and quantify its long-term impacts. In this issue of Paediatric and Perinatal Epidemiology, Guo and colleagues [5] performed an analysis of the Global Burden of Disease (GBD) 2021 study to examine the incidence and health burden of maternal obstructed labour and uterine rupture (MOLUR). The GBD dataset spans 204 countries and territories and employs standardised methodologies, enabling global, regional and national comparisons across 371 diseases and 88 risk factors. In their analysis, which covers a 22-year period, Guo and colleagues reported 16,066,975 cases of MOLUR in 1990 compared to 13,471,093 cases in 2021. This represents a notable decline accompanied by a reduction in disability-adjusted life-years (DALYs) from 1,794,034 to 1,067,270—a 40.5% decrease. Similar declines were observed in the global age-standardised incidence rate and the global age-standardised DALY rate. However, stratified analyses based on the socio-demographic index (SDI) revealed persistent disparities, with lower-SDI regions experiencing disproportionately higher rates of MOLUR than higher-SDI regions. The findings from Guo's study provide critical insights into global MOLUR trends that can inform public health priorities. Several strengths of the study bolster its conclusions, including the use of a large, well-characterised dataset and a focus on DALYs, which account for years of life lost and years lived with disability and capture the broader health impact of MOLUR that a singular focus on mortality may obscure. Additionally, the authors employed various analytical approaches, including trend, prediction, health inequality and frontier analyses, to comprehensively evaluate the health burden associated with MOLUR. Despite these strengths, the study raises important questions about the validity of MOLUR as defined by the GBD study as a composite exposure and the challenges of comparing data across socio-economic regions. These issues warrant further discussion and careful consideration. The definition of MOLUR in the GBD study encompasses several acute events associated with obstructed labour, including failure to progress, cephalopelvic disproportion (CPD), non-vertex foetal positioning, uterine rupture and obstetric fistula [6]. This definition aims to capture the full spectrum of obstructed labour and its sequelae. However, including these components raises concerns about the validity of MOLUR as a composite exposure. Not all components of the MOLUR composite are consistently tied to obstructed labour. For example, failure to progress in labour is defined as ‘the lack of advancement of the presenting part of the foetus despite strong uterine contractions’; CPD refers to ‘foetal size being too large for the maternal pelvic dimensions’ and non-vertex foetal positioning includes ‘any foetal position other than head down during labour’. None of these definitions include time parameters, making it challenging to distinguish prolonged from obstructed labour, a distinction that is critical to understanding differences in clinical outcomes. Additionally, including the parameter ‘any foetal position other than head-down during labour’ without accounting for a time parameter introduces further complexity, as many pregnancies in non-vertex positions result in successful deliveries, both vaginally and via caesarean, without leading to prolonged or obstructed labour. This lack of specificity complicates efforts to identify when dysfunctional labour transitions from prolonged to obstructed, which has clinical implications for outcomes reported and the impact on DALYs worldwide [7]. Refining the MOLUR composite, particularly by incorporating time parameters, may make it easier to differentiate between prolonged and obstructed labour, leading to more accurate and meaningful clinical assessments and improved reporting of outcomes and DALYs across varied SDI regions. On the other hand, uterine rupture and obstetric fistula are complications more closely associated with obstructed labour, although they can also occur in different contexts. Uterine rupture, for example, may result from labour in a scarred uterus, while obstetric fistulas can arise from poor healing of complicated perineal lacerations or improperly repaired perineal lacerations. Despite these limitations, linking uterine rupture and obstetric fistula with the other components of MOLUR (such as failure to progress, CPD or non-vertex positioning) or associated clinical sequalae (such as foetal death) may offer a more accurate representation of obstructed labour. A sensitivity analysis examining the degree to which MOLUR captures obstructed labour could provide valuable insights. We acknowledge that the limitations of the GBD dataset preclude such an analysis. Interpreting MOLUR across socio-economic regions presents additional challenges. A limitation of the GBD study is the source and accuracy of MOLUR data from low- and middle-income countries. It is unclear if data from countries that do not have national registries can or should be trusted. Data from most of these countries come from a cross-sectional survey, indeed many are based on a single survey. In addition, the authors age-standardised the MOLUR incident rates using the world population rather than age-standardising to specific countries. While intended to facilitate comparisons across countries, this may create a misleading picture since the age distribution in developing countries is not comparable to that of low-income countries. This is a notable limitation underscored by the observation that 17% of the world's population lives in high-income countries compared to 74% in middle- and 10% in low-income countries. There are also considerable despite its limitations, the study by Guo and colleagues differences in healthcare access and availability of healthcare interventions and resources across SDI regions. In high-SDI regions, prolonged labour is often managed with timely caesarean delivery, reducing the likelihood of complications such as uterine rupture or obstetric fistula. In these settings, access to surgical interventions ensures that labour rarely progresses to become obstructed. If a woman or birthing person presents with prolonged labour in these settings, early diagnosis and timely delivery by caesarean delivery can mitigate some of the serious complications related to obstructed labour. In contrast, in low-SDI regions, limited access to caesarean delivery and the heightened risks and complications associated with surgery, even when available, make severe complications from obstructed labour far more common. Abebech's story is illustrative of this disparity: after labouring at home for several days without access to medical care, she faced the full spectrum of risks associated with obstructed labour, resulting in poor clinical and social outcomes. The authors of the study acknowledge some of these limitations and point to the rising prevalence of caesarean delivery worldwide as a potential explanation for the observed declines in MOLUR rates. Despite robust methodology, these limitations nonetheless highlight the need for cautious interpretation. Despite its limitations, the study by Guo and colleagues [5] adds to our understanding of the global health burden of MOLUR. It underscores the importance of addressing disparities in maternal health outcomes. The observed declines in the incidence and DALYs associated with MOLUR over the past two decades likely reflect improvements in access to healthcare, maternal education and economic development, a trend that aligns with the principles and targets of the Sustainable Development Goals to promote health, gender equality and economic growth [8]. Notably, the study suggests disparities persist even among low- and high-SDI regions. This highlights the need for continued targeted approaches to improve outcomes that may differ in low- and high-SDI regions. Further research is needed to address the current study's limitations and improve our understanding of obstructed labour and its sequelae. Redefining MOLUR by including time parameters and other contextual factors (e.g., foetal death) could enhance its validity as a composite exposure. While this study may provide the best contemporary insight into global MOLUR trends at this time, refining our definitions and improving our understanding of obstructed labour with the relevant stakeholders is an essential step towards a future where no person has to endure the suffering and long-term consequences experienced by Abebech and others. Justin S. Brandt: conceptualization, writing – original draft, review, and editing; Sasha Hernandez: writing – review and editing. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.