Pregnant women have been warned to avoid the chemical BPA, found in canned food and plastics, which brings an 80% increase in risk of miscarriage / Rex Features

One of the first studies looking at the evidence in humans shows worrying link between chemical BPA and infertility

Pregnant women should avoid eating canned food, heating up meals in plastic and drinking from bottles which have been left out in the sun, an influential study in the US has found.

Scientists from Stanford University said chemicals from such products leak into food and drink, leading to an 80 per cent increase in the risk of miscarriage. They issued the same advice to men whose partners are trying to conceive, because of a similarly negative impact on male fertility.

While advice to pregnant women has suggested avoiding canned foods for some time, this is one of the first extensive research projects carried out on the evidence in humans, and has been presented at the American Society for Reproductive Medicine’s annual conference in Boston.

It suggests that a substance which can get into food from packaging processes – the chemical bisphenol-A (BPA) – comes with a marked and observable threat to the survival of a foetus.

BPA is contained in many cans, plastic containers and even shopping receipts, making it almost impossible to avoid the chemical altogether, the authors of the US study said.

The researchers did provide some advice as to how best a woman could limit the risk of exposure.

Lead author Dr Ruth Lathi, a reproductive endocrinologist at Stanford University, told the Telegraph: “This is important because miscarriage is a very common occurrence and human exposure to BPA is near-ubiquitous.”

“There are some simple things that people can do but it’s impossible to avoid it completely.

“Avoid anything that involves cooking or warming food in plastic as the chemicals leak out of plastic materials at a higher rate at higher temperatures.“

Even shopping posed a risk, she suggested, because many cash register receipts are coded with resin containing BPA.

“Avoid canned food, avoid cooking or heating plastic and then avoid unnecessary cash register receipts. Those are simple things that don’t cost a lot of money and are easy to do,” said Dr Lathi.

The Natural Hydration Council (NHC), which represents producers of naturally-sourced bottled water in the UK, said British water bottles are made from PET plastic that does not contain BPA.

“The plastic material used to contain naturally-sourced bottled waters found on UK supermarket shelves is made of PET (Polyethylene Terephthalate),” the NHC said. “There is no Bisphenol A (BPA) in PET plastic. PET is the main packaging used for beverages, it is completely safe and complies with all European and national legal requirements.”

The US research was conducted with 114 pregnant women who had some form of history with infertility or miscarriage – a group which is particularly at risk from the impact of BPA.

The scientists analysed quantities of BPA in the women’s blood, and found that those with the highest levels had an 80 per cent greater risk of miscarriage than those with the lowest level. Across the study, 68 of the 114 women miscarried.

Dr Linda Giudice, ASRM President, said that while there have been previous studies which looked at the impact of chemicals on those with fertility problems, the findings of this study suggest BPA could have a damaging impact on a far larger group of people.

She said: “These studies extend our observations to the general population and show that these chemicals are a cause for concern to all of us.”