Imagine having a baby and, unfortunately, that baby dies before reaching the age of one. As sad as this is to read about, this is the reality that faces many people worldwide. This occurrence is known as infant mortality. To measure how often this occurs, the Infant Mortality Rate is used. But how exactly is this defined? Are there advantages or limitations to the infant mortality rate? How do countries rank around the world according to this measurement? Let's find out!
Infant Mortality Rate Definition
Infant mortality rate (IMR) is perhaps one of the most commonly used measures of development. In addition to being an indicator on its own, it also acts as a proxy for indicators of economic, social or environmental development, such as the level of health in a country.
The infant mortality rate is the number of deaths that occur in children under the age of one per 1,000 live births per year (or given period)1,2.
In the strictest sense, the IMR is not actually a rate. Instead, it is the measure of the probability of a child born in a specific time period dying before their first birthday and expressed as a rate3. The IMR does not include stillbirths. These are recorded/measured separately.
Stillbirth refers to fetuses that die at or after 20 weeks of pregnancy.4
Calculating the Infant Mortality Rate
The infant mortality rate is calculated by using the following formula:
(D0-1 / B) X 1000
Where:
D0-1 = Number of deaths in the first year of life
B = Total number of live births
D0-1 = 10,200
B = 235,000
IMR = (10,200 / 235,000) x 1000
= 0.043 x 1000 = 43
Therefore, IMR = 43 per 1,000
Factors affecting Infant Mortality Rate
The infant mortality rate is affected by several external factors. Below are some of the factors that can have an impact on infant deaths and influence the infant mortality rate.
| Factor | Details |
| Age of the child bearer at the time of childbirth | Studies have shown that infant deaths are higher among mothers under the age of 20 and over 40. |
| Multiple births | The greater the number of births for a mother increases the infant mortality rate. This is because there is less recovery time for the mother. There may also be food shortages for families with multiple children. |
| Access to prenatal care | Access to proper prenatal care reduces the IMR. |
| Level of nutrition | Many infant deaths are tied to a lack of proper nutrition. Higher levels of nutrition result in lower IMR. |
| Level of sanitation and water quality | Poor sanitation and water quality are significant causes of infant mortality in less economically developed countries. Poor water quality leads to a lack of proper hydration, which can lead to death in an infant. Poor water quality also limits hygiene, which can also result in infant death. |
| Fertility rate | A reduction in the fertility rate results in lower IMR. Higher IMR can also reduce fertility rates. |
| Income per capita | Higher per capita income results in lower IMR. |
| Female participation in the labour force | Generally, the more women are involved in the workforce, the fewer children they will have. This reduces the IMR. |
| Female literacy rates | Women with higher levels of education tend to give birth later and seek better health care. Therefore, higher female literacy rates lead to a lower IMR. |
Table 1 - Factors affecting infant mortality rate
Fig. 1 - the relationship between fertility rates and infant mortality rates 1950-2010
Infant Mortality Rate by Country Rank
Globally, as of 2015, the average infant mortality is five times smaller than in 19505. While this represents significant global progress towards reducing infant mortality, it's essential to recognise that there are spatial variations in the infant mortality rate. Typically, more economically developed countries tend to have lower IMRs than less economically developed countries. This is because the latter usually have issues related to health care, nutrition and food insecurity, and high birth and fertility rates.
Take a look at the overview below:6
- The average global infant mortality rate was 27.4 per 1,000 in 2020.
- According to the 2020 worldwide IMR data, high-income countries had the lowest average rate of 4 per 1,000.
- Middle-income countries had an average rate of 26 per 1,000.
- Low-income countries had an average rate of 47 per 1,000, more than 10 times the rate of high-income nations.
- When disaggregated into regions, the European Union and Euro area countries have the lowest average IMR of 3 per 1,000.
- Sub-Saharan Africa had the highest average at 50 per 1,000.
- Areas considered fragile and conflict-affected have an average IMR of 52 per 1,000.
- On an individual country level, in 2020, Iceland ranks first with an infant mortality rate of 1.54 deaths per 1,000 live births.
- Sierra Leone ranks last with 80.10 deaths per 1,000 live births.
Fig. 2 - spatial variations in global infant mortality rates
Infant Mortality Rate UK
The United Kingdom experienced a fairly notable decline in its infant mortality rate from 23 per 1,000 in 1960 to 4 per 1,000 in 2020, ranking 34th on the global IMR listing7. The significant decrease can be attributed to improvements in health care, particularly prenatal and neonatal care. Additionally, the IMR has been mostly stable from 2014 to 2020.
Despite this substantial decline over the past 60 years, the UK actually has a higher IMR than many other high-income nations that also have universal healthcare. Furthermore, there are disparities in infant mortality between the wealthier and the poorer areas in the UK, i.e., infant mortality is higher in poor neighbourhoods than in affluent neighbourhoods. The factors that influence the IMR in the UK include, but are not limited to, maternal age, low birth weight and babies being born before 24 weeks gestation (developing in the womb).
Sudden infant death syndrome (SIDS), also sometimes called "cot death", refers to the unexpected, unexplained, or sudden death of a healthy baby under the age of 1. SIDS mainly occurs in the first 6 months of life and is more common in boys than girls. It typically occurs while the baby is sleeping, however, it can also occur while the baby is awake. There are about 200 cases of SIDS annually in the UK.
Advantages of Infant Mortality Rate
Let's examine some of the advantages of using infant mortality rates as a development measure.
- The infant mortality rate is a good indicator of the overall health of a country or community. The causes of infant mortality can be related to the factors that measure well-being.
- The IMR can help governments and health ministries make decisions on the allocation of resources.
- It is a fairly universal measure, as states typically mandate that both births and deaths be registered. Hence, recorded data is easily retrieved.
- It is fairly easy to calculate, understand and interpret.
Limitations of Infant Mortality Rate
As with any development indicator, the infant mortality rate has its disadvantages. Below, we shall explore some of the limitations of the infant mortality rate.
- In many countries, the reported number of infant deaths is inaccurate, as there is an under-registration of infant deaths. This is particularly true of remote areas in developing nations.
- Infant mortality rates are calculated on a national basis, and therefore they hide the inequalities in infant mortality that may exist within a particular country (as you would have read earlier about the UK).
- The IMR is used as a proxy for the health of a country. As a result, it is often the focus of health policies. These policies may cause the infant mortality rate to decline, but the overall health of the country may remain stationary or even decrease. This is because infant mortality has been prioritised over all other areas of health.
- There is some discrepancy in the definition of the term live birth; recorded mortality figures may vary across countries, which likely makes comparisons a bit problematic. Austria, for example, uses the World Health Organisations' (WHO) definition of live birth. Germany uses a slightly modified version of this, while Japan uses a completely different definition of live birth.
- It is often assumed that high IMRs are a result of socioeconomic factors. However, they can also be a result of political reasons. An example is China's One Child Policy; this policy slowed down the reduction in IMR.
Fig. 3 - China's one-child policy facts and figures
Infant Mortality Rate - Key takeaways
- The infant mortality rate is the number of children who die before their 1st birthday per 1,000 live births for a given period.
- There are a number of socioeconomic factors that influence the infant mortality rate, such as the age of a child bearer at the time of childbirth, or the level of nutrition, for example.
- In 2020, the average global infant mortality rate was 27.4 per 1,000. Iceland has the lowest infant mortality rate, while Sierra Leone has the highest.
- The UK ranks 34th in terms of infant mortality rate. There are also differences in the value of the IMR within the UK.
References
- D.D. Reidpath and P. Allotey, Infant mortality rate as an indicator of population health. Journal of Epidemiology and Community Health, Vol. 57., 2003.
- CDC, Infant mortality, 2022.
- WHO, Infant mortality rate (between birth and 11 months per 1000 live births, The global health observatory, 2022.
- NIH, Stillbirth, 2022.
- Max Roser, Hannah Ritchie and Bernadeta Dadonaite, Child and Infant Mortality, Our World in Data, 2019.
- The World Bank, Mortality rate, infant (per 1000 live births), 2022.
- The World Bank, Mortality rate, infant (per 1000 live births) - United Kingdom, 2022.
- Fig. 1: plot of infant mortality and total fertility rates 1950-2050 selected countries (https://commons.wikimedia.org/w/index.php?curid=11888313) by Fm122 (https://commons.wikimedia.org/w/index.php?title=User:Fm122&action=edit&redlink=1) licensed by CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0/deed.en)
- Fig. 2: infant mortality rate, 2020 (https://ourworldindata.org/grapher/infant-mortality) by Our World in Data (https://ourworldindata.org/) licensed by CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/deed.en_US)
- Fig. 3: China's one child policy (https://www.flickr.com/photos/46756575@N00/5576987758) by Nuno Luciano (https://www.flickr.com/photos/nunoluciano/) licensed by CC BY 2.0 (https://creativecommons.org/licenses/by/2.0/)
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A variety of factors affect infant mortality rate, including, the child bearer's age at time of delivery, multiple births, access to prenatal care, nutritional levels, water and sanitation levels, fertility rate, per capita income, female labour force participation and female literacy rates, amongst others.