Pregnant women in areas where farming and agriculture are large industries may be at risk of being exposed to a chemical that has been linked to cancer. 

A study published in Agrochemicals found the percentage of pregnant women testing positive for dicamba, a chemical herbicide, increased from 28 percent between 2010 and 2012 to 70 percent between 2020 and 2022. 

Researchers from Indiana, Washington and Quebec tested the urine of 61 pregnant women in Indiana, one of the biggest agricultural producers in the United States of mint, soybeans and corn.

Results also showed the concentration of the chemical increased from 0.066 micrograms of dicamba per liter of urine to 0.271 micrograms of dicamba per liter of urine. 

Dicamba is usually sprayed on top of crops – including soybeans – and the Environmental Protection Agency has previously acknowledged the substance can evaporate and spread through the air as a vapor. 

The study authors said their findings highlight the need to track exposure to the herbicide and monitor adverse maternal and neonatal side effects. 

The results come as there is an increase in use of and reliance on herbicides and pesticides in farming, prompting experts ‘to raise alarm bells’

While dicamba is sprayed on crops, the US Department of Agriculture has found residue of the chemical is minimal in foods. 

Therefore, the USDA said it is more likely people are exposed to the chemical through inhalation and contaminated drinking water. 

A 2020 study found dicamba was associated with an increased risk of liver and bile-duct cancers, but more research is needed to learn the full effects. 

The study also looked at the presence of another chemical in the women’s urine, 2,4-dichloroacetic acid, better known as 2,4-D. 

This chemical is also a common herbicide. 

While it was detected in 100 percent of women’s urine, the results showed detectable, but not significant increases in concentration levels from 2010 to 2012. 

The effects on the body of 2,4-D are less known, but animal studies have shown exposure to it during pregnancy was associated with lower body weight and changes in offspring behavior.

Other research has shown there is an increased link to lymphoma, and long-term exposure may result in kidney and liver damage. 

The researchers stated in their study that reliance on herbicides has drastically increased over the last decade. 

Paul Winchester, a professor of pediatrics at the Indiana University school of medicine – who was not involved in the study – told The Guardian: ‘These are two chemicals we’re concerned about because of their increasing use.’

A similar recent study found four out of five Americans were testing positive for another farming chemical used as a pesticide – chlormequat. 

That study found 80 percent of people tested positive for the substance, which has been linked to reduced fertility, altered fetal development and early onset of puberty.

The results come as there is an increase in use of and reliance on herbicides and pesticides in farming, prompting experts ‘to raise alarm bells’ because of the detrimental effects these chemicals have been associated with.