Child and infant mortality in England and Wales: 2012

• There were 2,912 infant deaths (deaths under 1 year) in England and Wales in 2012 compared with 3,025 infant deaths in 2011 and 6,775 in 1982
• In 2012 the infant mortality rate was 4.0 deaths per 1,000 live births, the lowest ever recorded in England and Wales, and compares with an infant mortality rate of 4.2 deaths per 1,000 live births in 2011 and 10.8 deaths per 1,000 live births in 1982
• Infant mortality rates were lowest for babies of mothers aged 30 to 34 years (3.4 deaths per 1,000 live births) and highest for babies of mothers aged under 20 years (5.5 deaths per 1,000 live births)

This statistical bulletin presents final statistics on infant deaths and childhood deaths that occurred in England and Wales in 2012. It also contains additional analyses by some of the key risk factors affecting infant deaths, including age of mother and birthweight. These characteristics are derived from linking the death registration to the corresponding birth registration record. Data are also available for babies born in 2011 who died before their first birthday: the 2011 birth cohort for infant deaths (254 Kb Excel sheet).

This is the first time that 2012 figures on infant and childhood mortality, based on occurrences, have been published by the Office for National Statistics (ONS). It is also the first time that the 2011 birth cohort data for infant deaths has been published.

Although infant mortality rates have continued to fall in England and Wales over the past 30 years, the rates of change varied over the period. The change in the first half of the period was more than twice that in the second half. General improvements in healthcare and more specific improvements in midwifery and neonatal intensive care can partly explain the overall fall in the rate of change.

Despite the downward trend, evidence in the Marmot Review: Fair Society, Healthy Lives noted that factors including births outside marriage, maternal age under the age of 20 and deprivation, were independently associated with an increased risk of infant mortality. The review went on to say that ‘low birthweight in particular is associated with poorer long-term health outcomes and the evidence also suggests that maternal health is related to socio-economic status’.

There were 2,912 infant deaths in England and Wales in 2012 resulting in an infant mortality rate of 4.0 deaths per 1,000 live births (the lowest rate ever recorded in England and Wales). Since 1982, when the rate was 10.8 deaths per 1,000 live births, there has been a 63% fall in infant mortality rates in England and Wales. This continues the overall decline in infant mortality rates in England and Wales over the past 30 years (Figure 1). The infant mortality rate in 2011 was 4.2 deaths per 1,000 live births.

Over the same period, there has been a similar fall in neonatal mortality rates (deaths under 28 days) and postneonatal mortality rates (deaths between 28 days and 1 year). The neonatal mortality rate fell by 56%, from 6.3 deaths per 1,000 live births in 1982 to 2.8 deaths per 1,000 live births in 2012. The postneonatal mortality rate fell by 74% over the same period, from 4.6 deaths per 1,000 live births in 1982 to 1.2 deaths per 1,000 live births in 2012.

In 2012 there were 3,558 stillbirths and 1,569 deaths at age under 7 days, resulting in a perinatal mortality rate of 7.0 deaths per 1,000 total births. Since 1982, when the perinatal mortality rate was 11.3 deaths per 1,000 total births, the rate has fallen by more than a third.

Linking birth and infant death records improves our understanding of the key characteristics of the baby’s parents that were registered on the birth registration record (see background note 4). In 2012, 98% of infant deaths in England and Wales were successfully linked to their corresponding birth registration record. The linkage rate for infant deaths has remained consistent since the linking exercise began.

The broad ONS cause groups showed that immaturity-related conditions, for example, respiratory and cardiovascular disorders, were the most common cause of infant deaths in 2012, with 45% due to these causes. Congenital anomalies were another major cause group, accounting for 34% of all infant deaths. Congenital anomalies accounted for 43% of all postneonatal deaths and 30% of all neonatal deaths.

The infant mortality rate for all infant deaths linked to their corresponding birth registration record was 3.9 deaths per 1,000 live births in 2012. For these linked deaths, infant mortality rates were lowest for babies of mothers aged 30 to 34 years (3.4 deaths per 1,000 live births) and highest for mothers aged under 20 years (5.5 deaths per 1,000 live births).

Low birthweight, one of the known risk factors for infant deaths, can be caused by a number of factors. For example, smoking has been identified as a major risk factor contributing to low birthweight. Babies born to women who smoke weigh on average 200g less than babies born to non-smokers (Health Development Agency, 2003).

In 2012 the infant mortality rates for very low birthweight babies (under 1,500 grams) and low birthweight babies (under 2,500 grams) were 173.0 and 35.2 deaths per 1,000 live births respectively. This is significantly higher than the rate of 1.3 deaths per 1,000 live births among babies of normal birthweight (over 2,500 grams).

For babies of low birthweight, the infant mortality rate was highest among mothers aged under 20 years (41.6 deaths per 1,000 live births) and lowest among mothers aged 30 to 34 years (31.9 deaths per 1,000 live births) (Figure 2). Although the neonatal death rates for low birthweight babies were lower than the corresponding infant mortality rates, they showed a similar pattern by mother’s age.

Significant differences in infant mortality rates by socio-economic group persist in England and Wales (Oakley et. al. 2009 (720.5 Kb Pdf)). One measure of social circumstances is that of occupational status. This information is collected at birth. Infant mortality rates were highest for the National Statistics Socio-economic Classification (NS-SEC) groups describing routine and manual occupations (Groups 5-7) with 4.6 deaths per 1,000 live births (the three-class version of NS-SEC has been used, see background note 9). In contrast there were 3.0 deaths per 1,000 live births for higher managerial, administrative and professional occupations (Groups 1.1, 1.2 and 2) and 3.8 deaths per 1,000 live births for intermediate occupations (Groups 3 and 4). For the 2012 data year, the way in which socio-economic status is reported has changed; details can be found in background note 8.

Similar patterns in perinatal mortality by socio-economic group were recorded with mortality rates highest for the NS-SEC groups describing routine and manual occupations (8.4 deaths per 1,000 total births). Higher managerial, administrative and professional occupations had a perinatal mortality rate of 5.6 deaths per 1,000 total births while for intermediate occupations the rate was 6.8 deaths per 1,000 total births. These variations may be the result of the link between lower socio-economic status and poorer maternal health which can ultimately affect infant mortality rates (Oakley et. al. 2009 (720.5 Kb Pdf)).

The infant mortality rate for babies of mothers born outside the UK was 4.2 deaths per 1,000 live births compared with 3.8 deaths per 1,000 live births for mothers born inside the UK. The highest infant mortality rates were for babies of mothers born in the Caribbean (7.4 deaths per 1,000 live births) and mothers born in Bangladesh and Western Africa (both 6.4 deaths per 1,000 live births). Babies of mothers born in the Caribbean also had the highest stillbirth rate (9.8 deaths per 1,000 total births). Differences in infant mortality rates by mother’s country of birth are likely to reflect underlying factors including mother’s age, together with a range of other socio-demographic characteristics mentioned earlier in this bulletin.

Between 1982 and 2012 the age-specific mortality rate for children aged 1 to 14 years fell by 62%, from 29 deaths per 100,000 population in 1982 to 11 deaths per 100,000 in 2012. The age-specific mortality rate for children aged 1 to 4 years fell by 66% over the same period, from 47 deaths per 100,000 population in 1982 to 16 deaths per 100,000 in 2012. Over the past 30 years child death rates from respiratory and circulatory diseases in England and Wales have been falling, as they have for the whole population, reflecting advances in medical care and preventative measures generally. In 2012 congenital related conditions and cancers were the most common form of death for children aged under 16 years.

Of the 723,913 live births in 2011, a total of 3,013 infants had died before their first birthday, resulting in an infant mortality rate of 4.2 deaths per 1,000 live births. There were 3,811 stillbirths and 1,633 deaths at age under seven days over the same time period, resulting in a perinatal mortality rate of 7.5 deaths per 1,000 total births (live births and stillbirths).

The infant mortality rate for multiple births in the 2011 birth cohort was over five times higher than for singletons (18.9 deaths per 1,000 live births compared with 3.7 deaths per 1,000 live births). This was most marked in the first 28 days of life (neonatal deaths) when the mortality rate for multiple births was more than six times higher than for singletons (15.6 deaths per 1,000 live births compared with 2.5 deaths per 1,000 live births). For those who survived beyond their first month but died before their first birthday (postneonatal deaths), the mortality rate was three times higher for multiple births (3.3 per 1,000 live births) compared with singleton births (1.1 deaths per 1,000 live births) (Figure 3).

On average, multiple births tend to have a lower birthweight than singletons, which is one reason why the infant mortality rate is higher for this group. Over half of multiple birth babies (56% of those with a known birthweight) were low birthweight (less than 2,500 grams) and 9.8% of those with a known birthweight were very low birthweight (less than 1,500 grams) (Figure 4).

In contrast, 5.5% of singletons were born with a low birthweight and 0.9% were very low birthweight. The main reason why multiple birth babies tend to have lower birthweight than singleton babies is because multiple births rarely go to term.

The highest infant mortality rates were for the extremely low birthweight babies (less than 1,000 grams). For singletons the rate was 313.0 deaths per 1,000 live births and for multiples the rate was 348.3 deaths per 1,000 live births.

Although most multiple births occur naturally, many occur as a result of fertility treatment. On average, 1 in 5 of In Vitro Fertilisation (IVF) pregnancies result in multiple births compared with 1 in 80 for women who conceive naturally (HFEA, 2013). In 2009, the Human Fertilisation and Embryology Authority launched the elective single embryo transfer (eSET) policy, which allowed centres to develop their own eSET strategy, with the aim to reduce the UK IVF multiple pregnancy rate to 10% over a period of years (HFEA, 2013).

Age of mother at birth using the 2011 birth cohort tables

Nearly two-thirds (64%) of all multiple births in 2011 were to women aged 30 years or over compared with 48% of all singleton births. The 2011 birth cohort tables for infant deaths show that mothers aged 40 years and over have the highest infant mortality rate for singletons (5.3 deaths per 1,000 live births). Younger mothers (under 20 years) have the highest infant mortality rate for multiple births (61.4 deaths per 1,000 live births).

Marital status and registration type using the 2011 birth cohort tables

The infant mortality rate for babies born inside marriage was lower than for those born outside marriage. The 2011 birth cohort for infant deaths shows that for singletons, there were 3.4 deaths per 1,000 live births inside marriage and 4.0 deaths per 1,000 live births outside marriage. For multiple births there were 15.7 deaths per 1,000 live births inside marriage and 23.5 deaths per 1,000 live births outside marriage.

The infant mortality rate for singletons was highest for those registered solely by their mother, or registered jointly by parents living at different addresses (5.2 and 5.0 deaths per 1,000 live births respectively). For multiple births the infant mortality rate was highest for those jointly registered by both parents living at different addresses (27.1 deaths per 1,000 live births) compared with 23.4 deaths per 1,000 live births for those jointly registered by parents living at the same address. The very small numbers in these groups affects the robustness of estimated mortality rates. Differences in mortality rates by marital status and birth registration type will also reflect complex underlying factors including mother’s age and social circumstances (Messer, 2011).

For married women the infant mortality rate for singleton births was higher for women who have previously had three or more children (5.3 deaths per 1,000 live births) compared with women who have had no previous children (3.7 deaths per 1,000 live births). Other factors may be relevant here, especially the mother’s age. For multiple births, the infant mortality rate was higher for women who have had no previous children (20.8 deaths per 1,000 live births).

Socio-economic status using the 2011 birth cohort tables

The 2011 birth cohort tables for infant deaths show that for singleton births, the highest infant mortality rate was for the National Statistics Socio-economic Classification (NS-SEC) groups describing routine and manual occupations (Groups 5-7) with 4.4 deaths per 1,000 live births (the three-class version of NS-SEC has been used, see background note 9). In contrast there were 2.7 deaths per 1,000 live births for higher managerial, administrative and professional occupations (Groups 1.1, 1.2 and 2) and 3.4 deaths per 1,000 live births for intermediate occupations (Groups 3 and 4). The same pattern was found for multiple births where there were smaller numbers, although the infant mortality rate for each group was between five and six times higher than for singletons. For the 2011 data year, the way in which socio-economic status is reported has changed; details can be found in background note 8.

Studies have shown that infant mortality rates are comparatively higher for low income families (Duncan and Brooks-Gunn, 2000). Mothers from routine and manual occupations are less likely to breastfeed than those from managerial and professional occupations (NICE, 2008) which can result in poorer immunity and poorer digestive health for the baby.

Infant mortality is seen as a key measure among health outcomes and there is a long established link between social and health inequalities, and infant mortality. The Department of Health (DH) is a key user of child mortality statistics. Infant mortality continues to take a central role in DH’s work on tackling health inequalities within the NHS Outcomes Framework 2014/15 and the Public Health Outcomes Framework.

There are also two specific users of the birth cohort data; the Department of Midwifery and Child Health, City University London; and Public Health England, who produce information, data and intelligence on people's health at a local level.

Other users of infant mortality data include academics, independent researchers, charities and media.

In January 2011, ONS began using ICD-10 v2010. A bulletin presenting the main findings from a Bridge Coding Study of 2009 Stillbirth and Neonatal Death Registrations (in which deaths were independently coded using v2001.2 and v2010), is available to help users understand the impact of this change on perinatal mortality statistics for England and Wales. The impact of ICD–10 v2010 on other deaths has been investigated in a separate study.

Planned changes to child mortality publications were outlined in an information note, available on the ONS website. These changes are being implemented.