Why we need a new measure of maternal health: the “lifetime risk of maternal near miss”

Ursula Gazeley

According to the most recent data from the World Health Organization, the lifetime risk of maternal death for a girl in Chad is a staggering 1 in 15, compared with 1 in 43,000 in Norway. This means that a girl in Chad has an almost 3000 times greater risk of dying from a maternal cause during her reproductive lifetime than a girl in Norway. The lifetime risk of maternal death is a useful measure to help us understand this global inequality in maternal mortality.

Maternal death is a tragic outcome of pregnancy. Although it is now rare in most parts of the world, progress is slowing. Additionally, many more women experience severe pregnancy complications that bring them dangerously close to death — so close that they are very likely to need emergency hospital care to save their lives. Such events are known as “maternal near misses” and are identified based on organ dysfunction (e.g. cardiovascular, respiratory, renal, haematological, hepatic or neurological) or complication-specific criteria, such as eclampsia, septicaemia or the need for hysterectomy or blood transfusion following obstetric haemorrhage.

Maternal near miss is an important maternal health outcome that reflects a health care system’s ability to provide emergency obstetric care and save a woman’s life when complications arise. Moreover, experiencing such severe complications can have long-term consequences for a woman’s physical, psychological, sexual, social and economic wellbeing.

There have been many calls to improve metrics on maternal morbidity, but relatively little progress in achieving this. In our recent study, published in the IJE, we introduce a new measure called the “lifetime risk of maternal near miss” to estimate the burden of maternal near miss morbidity across women’s reproductive lifetimes. This measure is analogous to the lifetime risk of maternal death, applied to life-threatening morbidity.

Existing indicators of maternal near miss prevalence — both the maternal near miss ratio and maternal near miss rate — only account for the level of obstetric risk associated with a given pregnancy. Neither measure accounts for the risks associated with fertility levels (women are at risk of experiencing a near miss during each pregnancy they have), nor women’s chances of surviving the reproductive ages of 15–49 years (to experience a near miss, a woman must not have died from a maternal cause or anything else). The lifetime risk of maternal near miss addresses these deficits and captures the dynamics associated with obstetric risk, fertility levels and women’s reproductive age survival.

In our study, we demonstrated use of this measure in Namibia. Our estimates indicate that a 15-year-old girl in Namibia faces a 1 in 38 lifetime risk of experiencing a maternal near miss, compared with a 1 in 142 lifetime risk of maternal death. When these risks are combined, the girl has a 1 in 30 chance of either dying from a maternal cause or experiencing a near-miss complication during her reproductive years.

This combined lifetime risk of maternal death or near miss is an important tool for advocacy — to highlight the impact of maternal health on women’s lives and the need for the global community to redouble its efforts to end preventable maternal mortality and morbidity. Estimation is needed across high- and low-income settings to draw attention to global inequities in adverse pregnancy outcomes.

To measure a country’s lifetime risk of maternal near miss, the ideal scenario is to use nationally representative data on the maternal near miss ratio (the number of maternal near misses per 1000 live births). The number of maternal near misses can only come from health care facilities. In countries where many women give birth at home, the number of live births should come from population-based estimates, so that births at home are also counted.

Across all world regions, births in health care facilities are lowest in sub-Saharan Africa. We will therefore overestimate the lifetime risk of maternal near miss if we rely on (unadjusted) facility-based estimates of births in these settings. In our study, we chose to apply this indicator to Namibia because, although it is a high-burden setting, high-quality national population-based maternal near miss surveillance data were available.

To start measuring the lifetime risk of maternal near miss globally, more countries need to routinely measure and report how many maternal near misses occur at the national level, as they do for maternal deaths. Several high-income countries already report this regularly (e.g. the Scottish Confidential Audit of Severe Maternal Morbidity and the Irish National Audit of Severe Maternal Morbidity). Aside from the maternal near miss ratio, all other data required to estimate the lifetime risk of maternal near miss are available via open access from World Population Prospects.

Read more:

Gazeley U, Polizzi A, Romero-Prieto JE, et al. Lifetime risk of maternal near miss morbidity: a novel indicator of maternal health. Int J Epidemiol 2023; 18 December. doi: 10.1093/ije/dyad169

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Ursula Gazeley (@GazeleyUrsula) is a PhD student at the London School of Hygiene and Tropical Medicine. Her research interests focus on measurement challenges of maternal mortality and morbidity, including outcomes beyond the 42-day postpartum period.