Environmental toxins and fertility – Research highlights from ASRM 2013
I just wanted to share some of the research highlights on environmental toxins and fertility from the annual meeting of the American Society of Reproductive Medicine (ASRM) held earlier this month in Boston.
Bisphenol-A (BPA) and Phthalates are two chemicals known as endocrine disruptors. Endocrine disruptors are chemicals that mimic or block hormones that regulate many of the body’s functions. In addition to disruption of hormones, these chemicals can also lead to gene mutations or alter gene expression. While infertility rates have increased in part due to couples putting off childbearing there are increasing concerns that exposure to environmental toxins are also playing a contributory role.
Let me start by saying that the research in this area is still relatively new, and there are still many questions left to be answered. Also know that research studies are only as good as their design and the individual(s) interpreting the data. By the way, there are research studies demonstrating that even with the same data set, two scientists may come to very different conclusions, because we all have a perceptual bias based on our own expectations, learning histories, whether we are invested in “finding” a certain result, etc. It also drives me crazy when you see the media create hype by saying, “Today, in the Journal of X, researchers found Y reduces Z” and then everyone runs out and thinks that adding or subtracting one thing from their diet or lifestyle will be a miracle cure. So please don’t do that. Things are usually a little more complex than that. But I digress, so let me get back to the research findings.
In a study by Louis et al., 501 couples trying to conceive were evaluated for BPA and phthalate levels in their urine. They found that certain concentrations of phthalates in males reduced the ability to reproduce by 20 percent and increased time to conception. [Note that earlier studies have also shown a relationship between phthalates and increased rates of DNA damage, low sperm count and abnormal sperm in men]. Surprisingly, this study found that higher levels of certain phthalates in females was associated with a shorter time to conceive and higher BPA concentrations were not associated with reduced ability to reproduce.
In contrast, a study by Lathi et al. did find that BPA had an impact on female fertility. In a sample of 114 women, BPA levels at four to five weeks of gestation were compared between those women who gave birth versus those with first trimester miscarriages. They looked at the women with the highest and lowest levels of serum BPA (upper and lower quartiles) and found that miscarriages were significantly more common in those women with the highest BPA levels, whether or not the fetus was chromosomally normal or abnormal. [Note: previous animal studies have shown a link between BPA and chromosomal abnormalities].
One study with PCOS patients found that higher levels of BPA in the follicular fluid may interrupt the conversion of androgen (testosterone) into estrogen and lead to an abnormal accumulation of androgen hormones.
The SY4W team will continue to follow the research and share what we learn with you. In the meantime, we suggest that you try to minimize your exposure to environmental toxins whether or not you are trying to conceive because endocrine disruption can impact other organ systems besides the reproductive system (e.g., your thyroid).
Just in case you’re not familiar with these chemicals:
Bisphenol-A (BPA) is a component used in many plastics. It is found in items such as plastic water bottles, the lining of steel food cans, dental sealants/fillings, food and milk carton linings, sales receipts, plastic cups and plates and containers used to store and reheat foods in microwaves. It was also used in many baby and toddler products, many of which were recreated to be “BPA-free”. However, new research has shown that Bisphenol-S (BPS), the chemical substituted for BPA in these products, is just as strong an endocrine disruptor as BPA!
Phthalates (pronounced thalates) – are found in many beauty products, often under the “guise” of fragrance (the FDA does not require companies to specifically list phthalates on labels). This includes things such as cosmetics, shampoos, lotions, nail polish, pill coatings, vinyl flooring, and plastic shower curtains.
So the bad news is that you cannot avoid all chemicals/toxins; the good news is that you can make better choices in many areas. More to come about environmental toxins on our website and blogs – so keep posted!!