The infant mortality rate in England and Wales continues to fall. In 2012, there were just 4.0 infant deaths per 1,000 live births – the lowest rate on record. This compares with 10.8 deaths in 1982, a 63% decrease. An infant death is defined as the death of a child less than 1 year old.
Figure 1: Infant mortality rates in England and Wales, 1982 to 2012
In the chart above, neonatal mortality covers deaths of infants less than 28 days old, whereas postneonatal mortality covers deaths from 28 days old to one year. Both these measures are reflected in the infant mortality rate.
Low Birthweight is a Major Risk Factor
The highest rates of infant mortality in England and Wales in 2012 were among women aged under 20 years, with 5.5 deaths per 1,000 live births. Women aged 40 and over had the second highest infant mortality rate with 5.2 deaths per 1,000 live births.
In addition to age, other influencing – and often related – factors include low birthweight and multiple births. For instance, older women are more likely to have multiple births, which increases the likelihood of the babies being of low or very low birthweight, increasing the risk of death during the first year of life.
In 2012, there were 173.0 deaths per 1,000 live births for very low birthweight babies (under 1,500 grams) and 35.2 deaths per 1,000 live births for low birthweight babies (under 2,500 grams). This compares with a rate of 1.3 deaths per 1,000 live births among babies of normal birthweight (over 2,500 grams).
Smoking is a major risk factor contributing to low birthweight. For the UK as a whole, mothers under the age of 20 had the highest levels of smoking (57%) before or during pregnancy in 2010. They were also almost six times as likely as mothers aged 35 or over to have smoked throughout pregnancy (35% and 6% respectively) (Health and Social Care Information Centre, 2012).
The infant mortality rate for multiple births is over five times higher than for single births. On average, multiple birth babies tend to have a lower birthweight than single birth babies, 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 of low birthweight, compared to 5.5% of single babies. Although 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). Nearly two-thirds of all multiple babies in 2012 were born to women aged 30 years or over.
Significant differences in infant mortality by socio-economic group persist in England and Wales. Infant mortality rates were lowest for the National Statistics Socio-economic Classification (NS-SEC) groups describing higher managerial and professional occupations (for example, doctors and lawyers). Infant mortality rates were highest in NS-SEC groups describing routine and manual occupations (for example, train drivers, shop assistants and waitresses). This may be caused by a link between deprivation, poor maternal health and low birthweight.
A Historical Perspective
In England and Wales, 95 out of every 1,000 children born in 1912 died before their first birthday. The decrease in infant deaths over the past century is due to advances in healthcare, including the control of infectious diseases and improved public health infrastructure, as well as specific improvements in midwifery and neonatal intensive care.
For the UK as a whole, infant mortality has been declining and is less than a quarter of what it was in 1970. The rate is currently similar to the average rate of countries inside the Organisation for Economic Co-operation and Development (OECD).
Figures are based on the number of deaths occurring in a calendar year (the ONS also publishes infant mortality statistics based on deaths registered in a year to provide more timely figures). For more information on the differences between registrations and occurrences please see Mortality Quality and Methodology Information (382.3 Kb Pdf) .