A new study suggests that bending forward frequently at work during early pregnancy may increase the risk of miscarriage. Researchers from Bispebjerg Hospital and the University of Copenhagen analyzed data from 803,829 pregnancies among 475,312 women in Denmark between 2004 and 2018.
Key Findings
Each additional hour of forward bending, particularly at a 30-degree angle, within an eight-hour workday was associated with a 36% higher risk of miscarriage. Similarly, every extra hour of walking was linked to an 18% higher risk, and standing for one more hour was associated with a 3% higher risk.
Study Details
Miscarriage affects about 15% of pregnancies. Known risk factors include parental age, smoking, night shift work, and exposure to air pollution and chemicals. Previous research on the effects of physical activities like bending, walking, and standing had been inconclusive. This study used an improved pregnancy-specific job exposure model combining activity tracker readings and expert evaluations of time spent standing, walking, and forward bending.
Of the pregnancies studied, 81,307 (about 10%) ended in miscarriage, a lower rate than the general prevalence. The findings were published in the journal Occupational and Environmental Medicine.
Limitations and Expert Commentary
As an observational study, it cannot prove causation. Limitations include lack of individual data on smoking during pregnancy and inability to adjust for lifting or other occupational exposures like shift work or chemicals. Prof Asma Khalil, from City St George's, University of London, noted that the results should not imply ordinary movement in early pregnancy is unsafe. She emphasized that the findings need replication before precise workplace guidance can be developed.
The researchers stated: “Although the mechanisms are not completely understood, these occupational exposures may affect placental perfusion or hormonal regulation in ways that could increase the risk of miscarriage.” Further studies are needed to confirm the findings and include potentially influential factors.
