Statistical bulletin: Infant and perinatal mortality in England and Wales by social and biological factors, 2010

Key points

• In 2010 the infant mortality rate was 4.2 deaths per 1,000 live births, the lowest ever recorded for England and Wales.
• Infant mortality rates were high among babies of mothers aged under 20 years and 40 years and over at 5.6 and 5.8 deaths per 1,000 live births respectively.
• Perinatal mortality rates were also higher for mothers in the 'under 20 and ’40 and over' age groups, at 8.3 and 10.2 deaths per 1,000 live births respectively.
• Very low birthweight babies (under 1,500 grams) had the highest infant and perinatal mortality rates, at 164.7 and 250.9 deaths per 1,000 live births respectively.
• Infant mortality rates were highest for babies registered jointly by parents living at different addresses and those registered solely by their mother, at 5.5 and 5.4 deaths per 1,000 live births respectively.

Summary

This bulletin on infant and perinatal mortality presents statistics on deaths and births that occurred in 2010.

In 2010, there were 3,076 infant deaths in England and Wales of which 3,022 (98 per cent) were linked to their corresponding birth records. The linkage rate for 2010 is comparable with that for previous years. This linkage enables analysis of infant and perinatal deaths by risk factors collected at birth registration.

Background

The level of infant mortality is seen as an indicator of the health of a nation, as calculated by infant mortality rates (IMRs) – deaths at ages under one year, per 1,000 live births. A range of biological and social factors are associated with high infant mortality. These include birthweight, mother’s age at birth of child, mother’s country of birth, marital status, parity (the total number of births a woman has had previously) and father’s socioeconomic status based on his occupation.

In 2010 of all linked infant deaths, 2,091 (69 per cent) occurred during the first 28 days of life (neonatal deaths) and 931 (30.8 per cent) between 28 days and one year (postneonatal deaths). The neonatal, postneonatal and infant mortality rates all declined between 2009 and 2010. The IMR was 4.2 deaths per 1,000 live births, with the neonatal mortality rate over twice the postneonatal rate (2.9 and 1.3 deaths per 1,000 live births respectively). Between 2000 and 2010 the IMR decreased by 23.6 per cent from 5.5 to 4.2 deaths per 1,000 live births ( Table 1 (117 Kb Excel sheet) ).

Infant mortality rates in England and Wales, 2000-2010

Download chart

• XLS format
  (77.5 Kb)

Biological factors

Biological factors such as birthweight, mother’s age and parity are key determinants of infant mortality.

In 2010, the infant mortality rates (IMRs) for very low birthweight babies (under 1,500 grams) and low birthweight babies (under 2,500 grams) were 164.7 and 36.8 deaths per 1,000 live births respectively, compared with a rate of 1.4 deaths per 1,000 live births among babies of normal birthweight babies (2,500 grams and over).

For stillbirths, the majority of very low birthweight babies (under 1,500 grams) were also of low gestational age (24–27 weeks). Most stillbirths (66 per cent) were preterm (less than 37 completed weeks of gestation). Additionally, of all preterm stillbirths, 63.5 per cent belonged to the very low birthweight category ( Table 3 (117 Kb Excel sheet) ).

IMRs vary by mother’s age at the time of birth of the baby. The age at which women have children has been shown to be related to their socio-economic status, job opportunities, access to further education and training in their employment (Cooper 2001). The IMR was highest among babies of mothers aged 40 and over and mothers aged under 20 (5.8 and 5.6 deaths per 1,000 live births). Babies with mothers in the 30–34 age group had the lowest IMR (3.8 deaths per 1,000 live births). Babies of mothers aged 40 and over had the highest stillbirth and perinatal mortality rates at 7.5 and 10.2 per 1,000 live births respectively. Babies of mothers aged 20 and under and 40 and over had the highest postneonatal mortality rates at 2.3 and 2.0 deaths per 1,000 total births respectively ( Table 4 (117 Kb Excel sheet) ).

IMRs also vary by birth registration type. Registration type is determined from the child’s birth records ( Table 6 (117 Kb Excel sheet) ) and is divided into four categories: within lawful marriage, jointly registered by both parents outside of marriage at the same address, joint registration with parents at different addresses and births solely registered by the mother.

The registration types with the highest IMR were births outside marriage registered jointly by both parents living at different addresses (5.5 per 1,000 live births), and births registered solely by the mother (5.4 per 1,000 live births). Sole registered births had the highest stillbirth rate at 6.8 per 1,000 live births. Many sole registered births are to younger women: in 2010, 20 per cent of all births to women under 20 were sole registrations, compared with 3 per cent to women aged 30–34.

Parity – the total number of births a woman has had previously – is only recorded for married women. The IMR was highest among mothers with three or more previous children (5.6 deaths per 1,000 live births) and lowest among mothers with one previous child (2.8 deaths per 1,000 live births).

Social factors

Infant mortality rates (IMRs) vary with social factors such as mother’s country of birth and the socio-economic position of the family, as derived from the information about the occupation of the father given at the registration of the birth.

Babies with mothers born in Central Africa (8.9 deaths per 1,000 live births), Pakistan (8.5 deaths per 1,000 live births) and Western Africa (7.3 deaths per 1,000 live births) had high IMRs compared with the overall infant mortality rate of 4.2 deaths per 1,000 live births (see Box 1 for country groupings).

The perinatal mortality rate was also high in babies of mothers born in Pakistan (13.2 deaths per 1,000 live births), Bangladesh (11.7 deaths per 1,000 live births) and Africa (11.3 deaths per 1,000 live births) compared with babies of mothers born in the UK (6.9 deaths per 1,000 total births). Babies with mothers born in Pakistan and Africa also had high neonatal mortality rates at 5.4 and 4.2 deaths per 1,000 live births respectively ( Table 5 (117 Kb Excel sheet) ).

Infant deaths are allocated to a socio-economic status using their father’s occupation at the death of the child, while births are allocated to a socio-economic status at the birth of a child. Infant deaths cannot be classified on the basis of father’s occupation at birth as only 10 per cent of all births are coded by father’s occupation. Also, information on the father’s socio-economic status is not available for births registered solely by the mother.

Outside marriage, babies of fathers in ‘semi-routine occupations’ had an IMR of 5.2 deaths per 1,000 live births compared with 2.5 deaths per 1,000 live births for babies of fathers in large employers and higher managerial occupations. Similarly, babies with fathers in semi-routine occupations also had the highest IMRs in the inside marriage category, at 5.8 deaths per 1,000 live births.

The ‘Other’ category comprises a mixed group including never worked; long term unemployed, students and those individuals whose occupational details could not be classified. Although this group had the highest rates for stillbirths and perinatal deaths, these figures should be interpreted with caution because the rates may vary between the different sub-groups ( Table 7 (117 Kb Excel sheet) ).

Causes of death

In England and Wales, stillbirths and neonatal deaths are registered using a special death certificate which enables reporting of relevant diseases or conditions in both the infant and the mother. For postneonatal deaths, a single underlying cause of death can be reported using the standard death certificate. ONS has developed a hierarchical classification system producing broad cause groups to enable direct comparison of neonatal and postneonatal deaths (Dattani & Rowan, 2002).

Seventy-three per cent of all infant deaths were related to events occurring in pregnancy (that is, congenital anomalies, antepartum infections and immaturity related conditions) as were 86 per cent of all neonatal deaths. For postneonatal deaths, 28.9 per cent were related to congenital anomalies, 11.9 per cent were from infections, 13.7 per cent were sudden infant deaths and 15.0 per cent were from immaturity related conditions. The majority of stillbirths were classified as antepartum deaths ( Table 8 (117 Kb Excel sheet) ).

Users and uses of infant mortality by social and biological factors statistics

This report on infant and perinatal mortality is an annual output, produced as a statistical bulletin. Figures are published for infant and perinatal mortality by baby’s age at death; birthweight; mother’s age; mother’s country of birth; marital status and type of registration and father’s occupation at death registration.

The report also presents figures for stillbirths by gestation and birthweight. Birthweight as a risk factor is presented as a grouped variable to draw distinction between death rates for low and normal birthweight babies. Deaths by mother’s age at the time of baby’s birth provides for useful comparison between younger and older age groups.

One of the key users of these statistics is the Department of Health (DH). Infant mortality continues to take a central role in DH’s work on health inequalities. Other users of this output include academics, independent researchers and the media.

Policy context

Infant mortality rates have been falling over the last few years and are at an all-time record low. However, health inequalities, such as differences in infant mortality rates by socio-economic group, persist.

Giving every child the best start in life is crucial to reducing these differences in infant mortality and in reducing health inequalities across the life course. Healthy Lives, Healthy People (2010), the public health white paper adopted an approach to tackle health inequalities by addressing the social determinants across the life course.

Building on the analysis and evidence in the Marmot review on health inequalities, Fair Society, Healthy Lives (2010), the white paper set out its theme of 'starting well' by emphasising the government's continued commitment to reduce child poverty, by investing to increase health visitor numbers, doubling by 2015 the number of families reached through the Family Nurse Partnership (FNP) programme, and refocusing Sure Start Children’s Centres for those who need them most.

Further information

Tables in this report (117 Kb Excel sheet)

Table 1            Infant deaths and infant mortality rates: all and linked deaths, 2000–2010,

Table 2            Live births, stillbirths and infant deaths by birthweight, 2010,

Table 3            Stillbirths: Gestation by birthweight, 2010,

Table 4            Live births, stillbirths and infant deaths by mother’s age, 2010,

Table 5            Live births, stillbirths and infant deaths by mother’s country of birth, 2010,

Table 6            Live births, stillbirths and infant deaths by marital status, parity (within marriage) and type of registration, 2010,

Table 7            Live births, stillbirths and infant deaths by National Socio–economic classification (NS-SEC), 2010,

Table 8            Live births, stillbirths and infant deaths by ONS cause groups, 2010.

References

1. Cooper, N (2001) ‘Analysis of infant mortality rates by risk factors and by cause of death in England and Wales’ In: Griffiths, Clare. Fitzpatrick, Justine. (Eds) DS 16. Decennial Supplement: Geographic Variations in Health. The Stationery Office.

2. Dattani N and Rowan S (2002) ‘Causes of neonatal deaths and stillbirths: a new hierarchical classification in ICD–10’, Health Statistics Quarterly 15 (72.2 Kb Pdf) , 16–22.

3. Department of Health (2010) 'Healthy Lives, Healthy People: Our Strategy for Public Health in England - White Paper and Impact Assessments'.

4. Marmot Review (2010) ‘Fair Society, Healthy Lives’.

5. Office for National Statistics (2001) The National Statistics Socio–economic Classification.

Background notes

1. Definitions used in infant mortality statistics:

   • Stillbirth – born after 24 or more weeks completed gestation and which did not, at any time, breathe or show signs of life,

   • Early neonatal – deaths under seven days,

   • Perinatal – stillbirths and early neonatal deaths,

   • Neonatal – deaths at under 28 days,

   • Postneonatal – deaths between 28 days and one year,

   • Infant – deaths under one year,

   • Rates – stillbirths and perinatal mortality rates reported per 1,000 total births (live and stillbirths). Neonatal, postneonatal and infant mortality rates are reported per 1,000 live births.
     
     

2. This report is based on data available up to 19 September 2011 and figures for 2010 are provisional. Figures reported in Table 1 for 2000 to 2009 are final.
   
   

3. A Summary Quality Report (122 Kb Pdf) for this release is available on the Office for National Statistics website. Further information on data quality, legislation and procedures relating to childhood, infant and perinatal mortality is available on the ONS website in Child Mortality Statistics Metadata (163.2 Kb Pdf) . More general information on the collection, production and quality of mortality data is available in Mortality Metadata (775.7 Kb Pdf) .
   
   

4. Details of the associated ICD-10 codes allocated to stillbirths, neonatal deaths and postneonatal deaths can be found in Annex J, K and L respectively and a description of the ONS cause group classification system on page xix of Mortality statistics: Childhood, infant and perinatal, 2007, Series DH3 no. 40.
   
   
5. Special extracts and tabulations of infant mortality data for England and Wales are available to order (subject to legal frameworks, disclosure control and agreement of costs, where appropriate). For such requests, enquiries should be made to:
   
   Child Health Team, Health and Life Events Division
   Office for National Statistics
   Government Buildings
   Cardiff Road
   Newport
   South Wales NP10 8XG
   
   Tel: +44 (0)1633 456398
   Email: cim@ons.gsi.gov.uk
   
   

6. As a valued user of our statistics, we would welcome feedback on this release. In particular, the content, format and structure. This is in line with the Health and Life Events user engagement strategy (95.1 Kb Pdf) , available from the ONS website.
   
   

7. Follow ONS on Twitter and Facebook.
   
   

8. For data for other UK countries please see the latest infant death statistics for Northern Ireland and Scotland.
   
   

9. Details of the policy governing the release of new data are available from the Media Relations Office. Also available is a list of the organisations given pre-publication access (53.8 Kb Pdf) to the contents of this bulletin.
   
   

10. National Statistics are produced to high professional standards set out in the Code of Practice for Official Statistics. They undergo regular quality assurance reviews to ensure that they meet customer needs. They are produced free from any political interference.
    
    

11. © Crown copyright 2011
    
    Under the terms of the Open Government Licence and UK Government Licensing Framework, anyone wishing to use or re-use ONS material, whether commercially or privately, may do so freely without a specific application for a licence, subject to the conditions of the OGL and the Framework.
    
    For further information, contact the Office of Public Sector Information, Crown Copyright Licensing and Public Sector Information, Kew, Richmond, Surrey, TW9 4DU.

    Tel: +44 (0)20 8876 3444
    Email psi@nationalarchives.gsi.gov.uk

12. Details of the policy governing the release of new data are available by visiting www.statisticsauthority.gov.uk/assessment/code-of-practice/index.html or from the Media Relations Office email: media.relations@ons.gsi.gov.uk

Statistical contacts