Women who continue to work into the final stages of pregnancy are likely to have babies with a lower birth-weight, which can increase the risk of poor health and slow development.
A major study found that those who remain at work beyond eight months have babies half a pound lighter on average than those who leave at between six and eight months. The effect is equivalent to smoking regularly, according to economists at the University of Essex.
A spokesman for the Royal College of Obstetricians and Gynaecologists (RCOG) said that the study should trigger further research.
The number of women working late into pregnancy in an attempt to maximise their time off afterwards has risen dramatically in recent decades. Professor Marco Francesconi, one of the