The death rate among babies fell to a record low in 2011, new statistics have revealed.
The latest figures published by the Office for National Statistics (ONS) show that there were 4.1 deaths per 1,000 children under the age of one last year.
The infant mortality rate in England and Wales has been steadily declining since 2000, when there were 5.5 deaths for every 1,000 babies.
According to the ONS, there are a wide range of biological and social factors linked to infant mortality rates.
It said: “These include birth weight, 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 the father’s socio-economic status based on his occupation.”
The latest figures show that the mortality rate last year was highest among babies born to mothers aged under 20 and those aged over 40, with 5.4 deaths per 1,000 births.
This fell to 3.7 deaths for every 1,000 births among mothers aged 35-39, the ONS said.
The mortality rate was also higher among babies with a low birth weight.
There were 36.4 deaths out of every 1,000 babies born weighing less than 2,500 grams. This rate increased to 172.1 deaths per 1,000 babies with a “very low” birth weight of less than 1,500 grams.
Experts at the ONS say infant mortality rates are a “key indicator” of the nation’s health.