Is a chemical used in plastic affecting female fertility?

Tegan Taylor: So I don't know if you've bought a drink bottle recently, Norman, but one of the things that's proudly displayed on so many drink bottles that I can see when they're being marketed is that they're BPA free, which is bisphenol A, it's a type of chemical that's in a lot of plastics.

Norman Swan: Yeah, and people have expressed concern about BPA, particularly in relation to its effects on fertility, which seems to be a recurrent theme in today's Health Report. 

Tegan Taylor: Well, Dr Emmalee Ford, who is one of the ABC's Top Five Scientists of 2024 so she came and did a residency with us, is a fertility expert, a reproductive scientist from Family Planning Australia, and she put together this story for us, looking into the evidence.

Rosie: We're doing reciprocal IVF, so we're aiming to use Sophie's eggs and me carry, and then vice versa is our goal for the second one in a few years time. We just got very conscious of doing things that were in our control, taking vitamins and swapping out all our containers for glass very slowly and all that kind of thing.

Emmalee Ford: This is Rosie from Newcastle, talking to me about going into IVF to conceive. Trying to give themselves the best chance, she and her wife, Sophie, cut out plastic containers for storing their food. Here's Sophie:

Sophie: At the beginning I would say we chucked out all of our old scabby plastic containers straight away, and then kept all the ones in reasonable nick, but the glass containers were built up over time, like we just sort of keep buying more and more. 

Emmalee Ford: The anxiety around plastics and fertility mostly centres on bisphenol A or BPA. It's part of a class of chemicals called endocrine disruptors, which means that it has hormone-like activity inside the body by binding to estrogen receptors. It's in plastics because it's heat stable and hard, and it's also found in things like the lining of canned foods and thermal paper used in some receipts. But repeated use, UV exposure and heat can see BPA migrate out of our food containers and into our mouths. There's been concerns about BPA for over a decade, mostly in the 2010s when it was banned in baby bottles in Australia. 

Alex Peters: We know from decades of research that the chemicals within plastics, including BPA, cause harm to various body systems. But what level of exposure, if any, is actually safe?

Emmalee Ford: Walking through the supermarket you can find heaps of plastic products claiming to be BPA free, like baby bottles, food containers and portable coffee cups. Food Standards Australia and New Zealand set our tolerable daily intake limit for BPA at .05 milligrams per kilogram of body weight per day. So for someone weighing 80 kilos, this is four milligrams of BPA a day. To try and limit our exposure to BPA, in come a range of replacements, other bisphenols called BPS, BPF, BPB and BPAF. These replacements are not regulated in the same way as BPA, but they do have a very similar chemical structure, but there's less overall research on these compounds compared to BPA. Someone trying to correct that is Alex Peters from the University of Newcastle.

Alex Peters: The effect of these alternatives or replacements, we are very quickly finding they have very similar effects to BPA. 

Emmalee Ford: Alex is the lead author of a study that's collected the known scientific evidence of the impacts of BPA and its alternatives on the ovaries and eggs within them. Alex's research looked at a range of evidence from cells in a dish to rodent studies and human clinical research. Full disclosure, I'm an associate lecturer at the University of Newcastle and was part of the study team. 

Alex Peters: What we found is a really large proportion, about 85% of these studies overall showed a negative impact on female fertility, particularly in the ovary or the egg, from BPA or BPA alternative exposure at levels that are in line with what we currently deem safe.

Emmalee Ford: But it's not just people in our institution who are concerned about BPA's effect on female fertility. 

Cecilia Sjoblom: It's a little bit like putting your head in the sand if you believe it's not going to affect us.

Emmalee Ford: This is Cecilia Sjoblom from Westmead Fertility Centre in Sydney. I wanted to find out how seriously she takes evidence about our environment when it comes to treating infertility.

Cecilia Sjoblom: I think we need to go really broad and look at all these environmental factors and how they're going to affect us in the future and our reproduction. If we want healthy reproduction, we have to look at what products we use and how we use them, but also the regulators have to be on board, because if we look at the studies, the limits set are well above what the studies indicate could be damaging.

Emmalee Ford: Understanding whether or not BPA will affect your fertility can feel a bit daunting because we can only control our environment so much. Alex says the onus needs to be on manufacturers and regulators to consider fertility when they're making decisions.

Alex Peters: Simple changes, like not warming up our food in plastic, that's a pretty important one. Where we can buy fresh fruits and vegetables rather than canned, because the lining of metal cans contains BPA, and that also goes for canned drinks.

Emmalee Ford: So, making small changes. But what is the real action that you want to see with BPA exposure regulation?

Alex Peters: For governments to actually take effects on fertility seriously and include them in their regulatory studies, because what we found is that not only are the regulations not appropriate for fertility, but they don't even really look at fertility. So that's the first thing. And the second thing is a re-evaluation and more comprehensive studies looking at more health outcomes. I would love to see our regulations reduced to a level that is comparable to those European levels.

Emmalee Ford: Alex is talking about the European Food Safety Authority. In 2023 they lowered their tolerable daily intake of BPA to two nanograms per kilogram of body weight per day, which is more than 500 times lower than Australia's tolerable daily intake. On the website of Australia's food safety regulator, they state that they have reservations about the approach taken by the European regulator. We reached out to Food Standards Australia and New Zealand, and a spokesperson said that based on studies they've done of the Australian food supply, detectable levels of BPA are below thresholds that pose a risk to human health. For Sophie and Rosie, they're just doing what they can within their own house and kitchen to maximise their chances of conceiving. And there's some good news on that front.

Rosie: I am actually pregnant now. We've just found out. I just wanted to wait till we did a heartbeat scan to tell people.

Emmalee Ford: Oh of course, of course. And congratulations!

Rosie: Thank you so much. We've only just found out. So far so good, but we're just crossing our fingers.

Tegan Taylor: Dr Emmalee Ford there, one of our Top Five Scientists for 2024, with that report.