Evidence links exposure to the chemical to a lower quality among eggs retrieved for in vitro fertilization. A study found that as blood levels of BPA in the women studied doubled, the percentage of eggs fertilized normally declined by 50 percent.
"The researchers noted BPA -- found in the urine of nearly everyone tested in a 2004 U.S. analysis -- is an endocrine disruptor that either mimics or blocks body hormones."
Bisphenol-A (BPA) is one of the world's highest production-volume chemicals and as a result of its widespread use has been found in more than 90 percent of Americans tested.
Of 115 published animal studies, 81 percent found significant health effects from even low-level exposure to BPA, and many of these involve reproductive and fertility problems.
In the latest study, women undergoing in vitro fertilization who had higher levels of BPA in their blood had 50 percent fewer fertilized eggs, which suggests the chemical is compromising the quality of women's eggs and perhaps contributing significantly to fertility problems.
How Does BPA Harm Your Fertility?
BPA is an endocrine disrupter, which means it mimics or interferes with your body's hormones and "disrupts" your endocrine system.
The glands of your endocrine system and the hormones they release influence almost every cell, organ, and function of your body. It is instrumental in regulating mood, growth and development, tissue function, metabolism, as well as sexual function and reproductive processes.
Chemicals like BPA can exert their effects by:
- Mimicking the biological activity of your hormones by binding to a cellular receptor. This can initiate your cell's normal response to the naturally occurring hormone at the wrong time or to an excessive extent (agonistic effect).
- Binding to the receptor but not activating it. Instead the presence of the chemical on the receptor prevents binding of the natural hormone (antagonistic effect).
- Binding to transport proteins in your blood, thus altering the amounts of natural hormones that are present in your blood circulation.
- Interfering with the metabolic processes in your body, affecting the synthesis or breakdown rates of your natural hormones.
The strongest evidence showing that exposure to environmental chemicals like BPA can lead to disruption of endocrine function comes from bizarre changes seen in a number of wildlife species, such as intersex fish, frogs developing a variety of defects like multiple testes or ovaries, and hermaphrodite bears, just to name a few.
But evidence is also very strong showing these chemicals are influencing humans, too, and leading to decreased sperm quality, early puberty, stimulation of mammary gland development, disrupted reproductive cycles and ovarian dysfunction, among numerous other health problems, like cancer and heart disease, as well.
What We Can Learn from History: The DES Disaster
During the 1950s and 1960s, the synthetic estrogen diethylstilbestrol (DES) was prescribed to 5 million pregnant women for the prevention of spontaneous abortion.
Many of these children ended up with physical deformities and developmental abnormalities, and some of the girls developed an unusual form of vaginal cancer when they reached puberty.
It was later found that exposure to DES alters the expression of HOXA10, a gene necessary for uterine development, while increasing the risk of cancer and pregnancy complications.
When studying the offspring of mice that had been injected with DES during pregnancy, researchers found changes in certain regions of the HOXA10 gene that persisted into adulthood.
This indicates that exposure to DES and similar substances results in lasting genetic memory, known as "imprinting," which is actually changing the structure of the HOXA10 gene.
Consequently, DES was banned in the 1970s, but the damage still lingers, and in some cases keeps showing up even in second-generation babies. And, although DES is no longer on the market, similar substances with estrogen-like properties -- such as BPA -- are.
How to Reduce Your Exposure to BPA
BPA in baby bottles has already been banned in Canada and several U.S. states. Other measures are being considered in 30 U.S. states and municipalities -- but at a federal level, the government is treading water and choosing to protect the interests of the chemical industry in favor of public health.
So for now the chemical is still widely used and found in such products as:
- Plastic water bottles
- Plastic gallon milk bottles
- Plastic microwavable plates, ovenware, and utensils
- Baby toys, bottles, pacifiers, and sippy cups
- Canned foods and soda cans (most have plastic lining in the cans)
- Tooth sealants
Avoiding BPA is therefore a matter of steering clear of these products by following these 11 tips:
- Only use glass baby bottles and dishes for your baby.
- Get rid of your plastic dishes and cups, and replace them with glass alternatives.
- Give your baby natural fabric toys instead of plastic ones, and only BPA-free pacifiers and teethers.
- Store your food and beverages in glass -- NOT plastic -- containers. Glass is the safest and most inert way to store your water and food, and is far better than ANY plastic (even BPA-free varieties).
- IF you choose to use a microwave, don't microwave food in a plastic container.
- Use glass, ceramic, or stainless steel travel coffee mugs rather than plastic or styrofoam coffee cups.
- Avoid using plastic wrap (and never microwave anything covered in it).
- If you opt to use plastic kitchenware, at least get rid of the older, scratched-up varieties, avoid putting them in the dishwasher, and don't wash them with harsh detergents, as these things can cause more BPA to leach into your food.
- Avoid using bottled water; filter your own using a high-quality filter instead.
- Before allowing a dental sealant to be applied to your, or your children's, teeth, ask your dentist to verify that it does not contain BPA.
- Avoid using canned foods (including soda cans) as the linings often contain BPA. If you do eat canned foods, choose only those that come in BPA-free cans.
Fortunately, there has been enough negative press about BPA that the public has been demanding safer, BPA-free alternatives -- and corporations have been responding.
Certain manufacturers, including Philips Avent, Disney First Years, Gerber, Dr. Brown, Playtex and Evenflow, have said they will stop making baby bottles that contain BPA, while several major retailers, including CVS, Kmart, Walmart, Toys R Us and Babies R Us are removing BPA-containing products from their stores.
So it is becoming gradually easier to find BPA-free alternatives for your family. Please support the companies that are moving in the right direction by removing this chemical from their products, and look for BPA-free labels on canned goods, baby bottles and children's toys before you buy.