Bending forward and prolonged walking during early pregnancy at work may be associated with an increased risk of miscarriage, according to a large Danish study. The research, published in Occupational & Environmental Medicine, examined over 800,000 pregnancies among more than 475,000 working women.
For each additional hour spent bending forward per workday during the first three months of pregnancy, the study found a 36 percent higher risk of miscarriage. The frequency of bending forward appeared to strengthen this association. Researchers noted that this refers to an average of one extra hour per eight-hour workday over the early pregnancy period, not isolated instances.
A weaker link was identified with prolonged walking at work, where each additional hour was associated with an 18 percent higher risk, although this pattern was less consistent. The study authors suggest that physical strain might potentially impact placental blood flow or hormonal regulation, though this remains uncertain.
However, researchers emphasize that the study is observational and cannot definitively establish cause and effect. They were also unable to fully account for other known risk factors such as smoking, alcohol consumption, caffeine intake, or pre-existing health conditions like PCOS or thyroid disorders.
Experts highlighted that the findings do not suggest that normal movement during pregnancy is unsafe. Instead, they likely reflect prolonged or repeated occupational postures, rather than typical daily physical activity. The researchers also pointed out that many miscarriages are due to genetic causes and are unlikely to be influenced by these behaviors. Previous prospective studies have not consistently reported similar associations.
In the UK, an estimated 250,000 pregnancies end in miscarriage each year, with most occurring within the first 12 to 13 weeks. The study authors state that further research is needed before any modifications to workplace guidance can be recommended.