Children may have poorer motor development - movement and coordination - if their mother experienced a lot of stress while pregnant with them, a new study suggests.

It is already known that stress during pregnancy can affect the behaviour and cognitive abilities of some children, however little research has been done on the potential impact of maternal stress on motor development.

Australian researchers decided to look into this further. They questioned almost 3,000 women when they were 18 weeks pregnant, and again when they were 34 weeks pregnant, about any stressful events during their pregnancy. These events included the death of a close relative, marital problems, financial struggles, losing a job and problems with the pregnancy itself.

The women's children were then assessed when they were 10 years old, 14 and 17. Their overall motor development and coordination were assessed using a 10-item movement test, which included a test of hand strength, walking along a line heel to toe, standing on one foot, moving small beads from one box to another and turning a nut onto a bolt.

The children were put into three groups - those whose mothers experienced no stress during pregnancy, those whose mothers had fewer than three stressful events and those whose mothers experienced three or more stressful events.

The study found that children born to mothers who experienced three or more stressful events during pregnancy produced lower motor development scores during all three age assessments - 10, 14 and 17 years.

It also noted that the biggest differences in motor development outcomes were between those whose mothers had experienced no stress and those whose mothers had been very stressed.

The study also found that motor development was poorer in those whose mothers experienced a lot of stress in the later parts of their pregnancy.

The researchers noted that children with poorer motor competence can have problems with everyday fine and gross motor tasks such as writing, running and throwing. However with proper intervention, this can often be improved.

"Given our findings on the importance of mothers' emotional and mental health on a wide range of developmental and health outcomes, programmes aimed at detecting and reducing maternal stress during pregnancy may alert parents and health professionals to potential difficulties and improve the long-term outcomes for these children," commented Prof Beth Hands of the University of Notre Dame.

Details of these findings are published in the journal, Child Development.