BPA-free plastics may up reproductive problems: Study

BPA-free plastics -- touted to be a safe alternative for babies and pregnant women -- may cause reproductive abnormalities for up to three generations, a study in mice suggests.

Twenty years ago, researchers made the accidental discovery that the now infamous plastics ingredient known as bisphenol A (BPA) had inadvertently leached out of plastic cages used to house female mice in the lab, causing a sudden increase in chromosomally abnormal eggs in the animals.

The team has found that the array of alternative bisphenols now used to replace BPA in BPA-free bottles, cups, cages, and other items appear to come with similar problems for their mice.

The findings, published in the journal Current Biology, were uncovered much as before as the researchers again noticed a change in the data coming out of studies on control animals.

They traced the problem to contamination from damaged cages, but the effects this time were more subtle than before, said Patricia Hunt of Washington State University in the US.

However, researchers were able to determine that the mice were being exposed to replacement bisphenols. They also saw that the disturbance in the lab was causing problems in the production of both eggs and sperm.

Once they got the contamination under control, researchers conducted additional controlled studies to test the effects of several replacement bisphenols, including a common replacement known as BPS.

Those studies confirm that replacement bisphenols produce remarkably similar chromosomal abnormalities to those seen so many years earlier in studies of BPA.

Hunt notes that the initial inadvertent exposure of their animals was remarkably similar to what might happen in people using plastics in that the exposure was accidental and highly variable.

Not all of the animals' cages were damaged, and so the findings differed among animals in different cages.

Although determining the levels of human exposure is difficult, the controlled experiments were conducted using low doses of BPS and other replacement bisphenols thought to be relevant to exposure in people using BPA-free plastics.

These problems, if they hold true in people as has been shown in the case of BPA, will carry over to future generations through their effects on the germline.

The researchers showed that, if it were possible to eliminate bisphenol contaminants completely, the effects would still persist for about three generations.