Expectant fathers preparing to cope with the financial burden of their partners taking time off after birth to care for their new baby might have to get used to a reduction of wages before the birth as well.

New research by a Dutch Professor shows that pregnant women are putting the lives of their unborn babies at risk if they work more than 32 hours each week in stressful jobs.

The research project, carried out by Professor Gouke Bonsel, involved 7000 expectant mothers and found babies born to stressed-out mums were up to 5 ounces lighter than the average birth weight.

Professor Bonsel, who set up the Amsterdam Born Children and their Development research group, said: "Women with high-stress jobs would do better to work no more than 24 hours from the beginning of pregnancy".

The findings would mean women should only work a 3-day week in the run up to having a baby something that would bound to have an affect on the family income.

The survey also found that pregnant women working long hours were also revealed as having an increased risk of developing pre-eclampsia, a serious complication caused by a defect in the placenta that restricts blood flow to the baby.