'Gender bending' chemicals from household goods like plastic packaging and make-up 'raise risk of miscarriages and Down's syndrome'Even low-level exposure can interfere with foetus
07:44 GMT, 25 September 2012
Harmful surroundings: Pregnant women could be at risk of miscarriages or having children with Down's syndrome because of exposure to chemicals in the environment
Chemicals in the environment may be harming unborn babies by raising the risk of miscarriages and Down’s syndrome, scientists warn.
U.S. researchers claim even low-level exposure through households goods while pregnant can interfere with the formation of eggs in the developing foetus.
It raises the possibility these hormones, widely used in plastic bottles, make-up and packaging, could be causing damage to future generations.
Scientists at Washington State University gave pregnant rhesus monkeys, whose reproductive systems are very similar to humans, a dose of Bisphenol A either in day pills or continuously via an implant in their arm.
The researchers say this dose is comparable dose to day-to-day exposure in humans, although other scientists argue it is hundreds of times higher and pregnant women should not worry.
In the monkeys’ female embryos, the egg cells failed to divide properly at an early stage and they were more likely to have the wrong number of chromosomes.
Many pregnancies with the wrong number of chromosomes will result in miscarriage, and those that do come to term may be born with genetic defects.
There were further problems in the third trimester as the structures holding the foetus’s eggs did not develop properly – leaving fewer functioning eggs.
The number of eggs a woman has is set when she is born, and determines how easy it will be to conceive and the length of time she is fertile.
Lead researcher Patricia Hunt said: ‘That’s not good because it looks to us like you’re just throwing away a huge number of the eggs that a female would have. It raises concerns about whether or not she’s going to have a really short reproductive lifespan.
Worrying finding: In tests on monkeys, a dose of a chemical caused embryos to develop the wrong number of chromosomes, which, as in humans, will result in miscarriage
She added: ‘The really stunning thing about this effect is we’re dosing grandma, it's crossing the placenta and hitting her developing foetus.
‘If that foetus is a female, it's changing the likelihood that that female is going to ovulate normal eggs. It’s a three for one hit.’
There are increasing concerns about these environmental chemicals, which are known as endocrine-disrupting or ‘gender bending’ because they mimic the effect of oestrogen in the body.
High levels in humans have been linked with obesity and behaviour problems, and it is feared they are leading to fertility problems such as low sperm counts in men.
This study, published in the Proceedings of the National Academy of Sciences (KEEP) follows on from similar findings from the same team in rats.
It was replicated in monkeys because critics said rats reproductive systems were different to humans and that the hormones levels were not comparable.
Professor Richard Sharpe, a world expert at the Medical Research Council in Edinburgh said most humans are exposed to bisphenol A but the levels are ‘extremely low’ and a lot of it will be neutralised in the gut and liver.
He said: ‘Exposure of body tissues is likely to be minimal; in fact, contrary to what the authors of this article state, the levels of free bisphenol A are too low to measure in normal humans.
‘The levels of exposure used by the authors in the present study are far in excess of human exposure, by many 100-fold, so raise minimal health concerns for pregnant women and their babies.
'In addition, the effects that are described are subtle and animal numbers are very small.’