Children of women who reported domestic violence in pregnancy or during the first six years of the child’s life are almost 50% more likely to have a low IQ at age 8, research finds.

In the study by University of Manchester epidemiologists, 13% of children whose mothers did not experience domestic violence had an IQ of below 90 at 8 years of age.

If their mothers experienced physical violence from their partner either in pregnancy or during the first six years of the child’s life, the figure rises to 22.8%.

The team led by Dr Kathryn Abel from The University of Manchester show the chance of a low IQ rises to 34.6% if the mother was repeatedly exposed to domestic violence.

That means children with mothers who repeatedly suffer domestic violence during pregnancy and the first six years of their child’s life are almost three times more likely to have a low IQ at 8 years of age, find researchers.

Low IQ is defined as an IQ score less than 90, where a normal IQ is considered to be 100.

The study examined the link between domestic violence - also called Intimate partner violence (IPV) - and child intelligence at 8 year’s old, using 3,997 mother child pairs from The University of Bristol’s Avon Longitudinal Study of Parents and Children.

The study, funded by the Wellcome Trust and Medical Research Council, is published in Wellcome Open Research.

ALSPAC follows children from pregnancy, and measures emotional and physical domestic violence – also known as intimate partner violence - from pregnancy until eight years of age.

The intelligence of the children was measured at eight years using the Weschler standardised IQ test.

Dr Abel said: “We already know that 1 in 4 women age 16 and over in England and Wales will experience domestic violence in their lifetime and that their children are at greater risk of physical, social and behavioural problems.

“We also know that intelligence in childhood is strongly linked with doing well in adulthood, though there has been little evidence about the risk of low IQ for these children.

“While we cannot conclude that IPV causes low IQ, these findings demonstrate domestic violence has a measurable link, by mid-childhood, independent of other risk factors for low IQ.”