Bending forwards and prolonged walking at work during early pregnancy may raise the risk of miscarriage, a study suggests. 

A large Danish study of more than 475,000 working women, covering over 800,000 pregnancies, examined whether physical activity at work in early pregnancy - defined as the first three months - is linked to miscarriage risk.

Miscarriage is relatively common but most cases are caused by chromosomal or developmental issues with the embryo rather than a mother’s everyday movements. 

However, some lifestyle and environmental factors may play a role.

The research, published in Occupational & Environmental Medicine, found that each additional hour spent bending forward per day was associated with a 36 per cent higher risk of miscarriage.

The more often people bent forwards, the stronger the link appeared to be. 

Researchers stress that this refers to an extra hour per eight-hour working day across early pregnancy, rather than a one-off instance.

They suggest physical strain could potentially affect blood flow to the placenta or hormonal regulation, although this remains uncertain.

The study also identified a weaker link with walking at work, with each additional hour associated with an 18 per cent higher risk, though this pattern was less consistent

Because the study is observational, it cannot establish cause and effect. 

Researchers were also unable to fully account for other known risk factors, including smoking, alcohol consumption, caffeine intake, or underlying health conditions such as PCOS or thyroid disorders.

Experts emphasise that the findings do not mean normal movement during pregnancy is unsafe. 

Instead, they likely reflect prolonged or repeated workplace postures, rather than everyday physical activity, and prolonged forward bending is relatively uncommon. 

They also note that many miscarriages are due to genetic causes and are unlikely to be influenced by these behaviours, and that previous prospective studies have not consistently found similar links.

In the UK, an estimated 250,000 pregnancies end in miscarriage each year, with most occurring within the first 12 to 13 weeks.

The findings highlight a potential occupational risk in early pregnancy but researchers say further studies are needed before any changes to workplace guidance can be justified.