A New Zealand study has found a locally sold tampon brand contains high levels of a hormone disrupting chemical. 

The brand - which remains unknown because it has not been named in the study - was among four that formed part of a pilot study carried out by Otago University’s Insitugen unit which looked at the potential health impacts of tampons made with synthetic fibres. 

Professor Alison Heather is the chief scientific officer at the Insitugen unit which oversees laboratory testing for steroid hormones to pick up drug cheats in sport. 

She says the results were surprising. 

“We didn't really expect to see oestrogenic activity, which we did. We went into the study with the idea that we wouldn’t find anything, however, for one brand we found that we did see oestrogenic activity,” she says.

Oestrogenic activity is a change in the body directly linked to the presence of oestrogen - or chemicals that mimic oestrogen. 

The study was commissioned by New Zealand-owned period product company Organic Initiative (Oi) to find out whether endocrine-disrupting chemicals - also known as EDCs which can mimic oestrogen - are present in four commonly available period products. 

The study found three of the four products, including Oi, did not have any disruptive activity but there was one product that showed a lot. 

“It’s quite surprising for anything to activate to that level because the chemical has to be in a high enough concentration that would activate the receptor in our body that responds to oestrogen, so it’s at a fairly high level,” she says. 

It was Organic Initiative’s decision not to name the brand publicly. A spokesperson for Organic Initiative says it made the decision not to disclose the leaching brand because the study tested only a small selection of tampon brands and not all the tampon brands sold in supermarkets. 

Oi says it feels it’s unfair to name and shame just one brand when not all products have been tested.

Professor Heather says researchers went back and purchased the brands again and retested them and the different batches came back with the same results. 

What EDCs can do inside your body

Endocrine-disrupting chemicals - also known as EDCs - are chemicals that can disrupt your hormones. 

In this case, the researchers found a chemical that mimic oestrogen, and other studies have shown similar chemicals can lead to health problems like endometriosis and in some cases cancer. 

“If we look at other studies where oestrogen BP mimicry chemicals have been investigated for different things, we know that these oestrogen mimicking chemicals can lead to oestrogen-related problems,” she says.

But Dr Heather says researchers don’t know what this particular chemical is yet or if it is able to leach out of the tampon, cross the tissue of the vagina, get into a woman’s bloodstream and cause a physiological effect. 

Are tampons regulated in NZ?

Tampons are regulated as medical devices by the Food and Drug Administration (FDA) in the United States but not here in Aotearoa. 

The Ministry of Business, Employment and Innovation is in charge of product safety and told Re: News it would take a look at the study’s findings. 

“MBIE will consider the most recent evidence in relation to this potential hazard, which will inform its prioritisation relative to other product safety risks,” it said in a statement. 

The study is small and has not been peer reviewed. 

Professor Heather says there is still a lot more work to do, and this study’s findings have created a lot more questions that need to be answered. 

“We’re going to look more at what’s in that particular brand. How common is this problem? And are there many female hygiene products that have this level of oestrogen activity?” she says. 

“We’ll have to identify the chemical and find out exactly what it is and then we can come back and say, ‘yep, this is the chemical and it’s linked to XYZ in the body”.

More stories:

Why I had an abortion: Young NZers share their stories

Despite abortion being decriminalised, it remains a divisive topic in New Zealand.

When your Asian parents won’t let you date until marriage

“No one lives a better double life than the oldest daughter of an Asian family."

Five rights renters have - but might not know about

Both renters and landlords have legal rights. As a renter do you know all your rights?