There has been a world-wide increase in the prevalence of women working during pregnancy. In 1995 in the UK, 66% of women of working age were in employment. This figure had risen to 69% by 200026 and continued to rise. In 2004, seasonally adjusted figures for the spring quarter showed that 45% of the employed population were women.

The majority of these (77%) were of child-bearing age (18–49 years old). Over half of women who are pregnant in the UK are in paid employment during their pregnancy and 37% were still working within six weeks of delivery.

Every year around 350,000 women continue to work during their pregnancy and, of these, 69% return to work soon after giving birth.

The majority of women remain well throughout their pregnancy. Pregnancy should not be regarded either as an illness or, generally, as a contraindication to work. Indeed there is some evidence of a beneficial effect of work on pregnancy. It has been suggested that the ‘reproductive experience’ of women who work is better than those who do not.58 Some studies show that women who are employed have a lower risk of preterm delivery than those who are not. However, a pregnant woman may be exposed, while at work, to particular hazards that might potentially cause adverse outcomes for mother or fetus. Therefore, where possible, steps should be taken to minimise exposure where there is sufficient evidence that the risk of maternal or fetal harm outweighs any benefit to health. A few workplace exposures (eg lead and ionising radiation)1,2 are well established as being harmful during pregnancy and the need to limit exposure is explicit in statutory instruments in the UK. However for many other common workplace exposures, including some physical hazards, the evidence to inform a balanced assessment of risk is not available, or is uncertain.