You’ve modified your diet, significantly cut down on alcohol and well, smoking was never your thing anyway. The next thing you might be wondering is about toxins and the potential impact that has on egg and sperm quality and the little embryo about to implant. If you believe the news environmental toxins are EVERYWHERE but do they really matter or is it yet another, hippie fad?
Call them toxins, environmental contaminants, chemical contaminants or environmental toxicants, the synthetic chemicals that we come across in our daily living seem to be linked more and more to declining fertility in ‘normal’ populations and poorer outcomes in the IVF world. These chemicals have been linked to all sorts of conditions including cancers, neurological conditions and even mental health conditions. For the purposes of your upcoming IVF cycle we are most concerned with link to a decline in fertility and poorer IVF outcomes.
Environmental contaminants are often referred to as being ‘endocrine disruptors’ as they can interfere with the bodies endocrine, or hormone, system and more specifically in this instance with estrogen. The chemicals do this by either mimicking how estrogen works, blocking its use or simply just interfering with the way it is made or controlled (National Institute of Environmental Health Sciences). Regardless of the exact mechanism, they are preventing the normal functioning of our endocrine system from happening and this has the potential to adversely impact on our fertility and IVF success. Endocrine disrupting contaminants are in many different substances (both natural and man-made) with some of the main ones being certain pharmaceuticals, dioxin and dioxin-like compounds, polychlorinated biphenyls, DDT and other pesticides, and plasticizers such as bisphenol A and phthalates. Endocrine disruptors have been given a bit of attention recently and are thought to be so important as they can travel vast distances both through air and up the food chain (1) meaning that their impact can be wide reaching. The two ‘plasticizers’ have particularly been topical recently and are further discussed here (though pesticides and other contaminants are also of importance and should be reduced where possible).
Ive heard of it… but what is BPA?
Bisphenol A, or BPA, is a substance that was primarily used in the manufacturing of plastics. It is still often used in lining tin cans and in some plastic drink bottles and is even used on the coating of til receipts that is then absorbed through our skin when handling the receipt (2). There have been small studies that have been conducted analyzing the levels of BPA in the blood of women undergoing IVF and it has been found that the higher the levels of BPA the lower the fertilization rates (3). Other studies have also shown that for women doing IVF, those with higher levels of BPA in their blood had lower numbers of eggs, less mature eggs and lower rates of fertilization (2).
BPA is found in many plastic containers and coatings and although the studies are small, at times contradictory and inconclusive, where possible it does seem like it is beneficial to limit the amount of BPA that you come into contact with (despite studies from the United States Food and Drug Administration highlighting that the level of BPA that is absorbed in day to day activities is within safe limits). This would include looking out for BPA free plastic containers (preferably glass containers because who knows what they are replacing the BPA with), limiting the amount of tinned food that you eat (as BPA is often in the coating) and avoiding drinking water from plastic bottles. Oh and if you work in retail try and reduce the amount of receipt handling you do – just to be safe.
Phthalates are a group of chemicals that are used to make plastics more flexible and harder to break (Center for Disease Control; CDC). They are also used to in anything that is fragranced and hence are found in many personal care products including perfumes, soaps, deodorants, hair sprays and are also in nail polishes. This is together with the hundreds of products including flooring, adhesives, detergents, lubricating oils, automotive plastics, plastic clothes such as raincoats and sometimes children’s toys, plastic packaging and medical tubing. It seems, phthalates are everywhere! Similarly to BPA we can ingest phthalates by ingesting them when we eat food that has contacted the plastic containers or particularly in the case of cosmetics and personal items absorbing them through our skin and even through inhalation. Once we have ingested phthalates they are metabolised by the body into metabolites are are then excreted from our body in urine.
It is by analyzing the metabolites in our urine that researchers are able to quantify how much phthalates a person has been exposed to and make comparisons to various outcomes, such as, oh I don’t know, the success of an IVF cycle. Before we look at IVF specifically, there is a significant body of research that has been done in animals implicating phthalates with poorer reproductive outcomes and also linking phthalates to an increase in oxidative stress in our body (particularly researched in men and pregnant women). From what I have seen though, whilst it seems increasingly undeniable that the influence of phthalates negatively impacts our IVF cycles the hard human evidence demonstrating its impact in women is still coming. However, a study in 2016 (4) reported that when analyzing the metabolites found in the urine of women undergoing IVF the higher the amounts of metabolite DEHP and DiDP found, the lower the number of eggs produced and number of mature eggs produced. Additionally, an increased presence of the metabolites DiNP and DiDP were associated with lower fertilization rates. This ultimately led the researchers to conclude that higher levels of DEHP ultimately led to lower clinical pregnancy and live birth rates. Whilst having high amounts of phthalates in your blood (and urine) isn’t going to be the only factor to make or break your cycle, or even be the major factor, it may be at the very least a significant risk factor and is certainly worth reducing your exposure where possible.
It should be noted though that not all studies support this. For example in 2017 a paper was published (5) that indicated that male, but not female, urinary concentrations of phthalates influenced blastocyst quality and another study reported that even though metabolite MEHP and MBP where found in follicular fluid and urine of females doing IVF these were not associated with the usual IVF parameters (which may include things like egg quality, number, fertilization rates etc).
As we have already stated though, regardless of the evidence being somewhat inconclusive, there does seem to be enough evidence to suggest that it is worthwhile reducing your exposure to endocrine disruptors as much as possible. So, how do we do this?
- Throw out the plastic storage containers in your house and investing in either glass or stainless steel. Watch out for plastic recycling codes 3, 6 and 7 as these may contain endocrine disruptors. Particularly avoid reheating your food in plastics as when the plastic is heated the integrity of the plastic is changed making it easier for the transfer of phthalates to your food.
- Try not to use cling film and other products to wrap your food in. Paper bags for sandwiches may seem like a throwback to the fifties but its at least worth a try. So is aluminum foil.
- Use ‘natural’ cosmetics products available such as those from Nourished Life (this is an Australian website but there are others in the US). Or if this proves to be cost prohibitive looking for products that are ‘phthalate free’ (and their derivatives). This can be tricky and they can hide so it pays to do your research as sometimes the name can be somewhat ‘hidden’. Remember products that have added fragrances nearly always contain phthalates so looking for ‘fragrance free’ is worth a try also.
- Reducing chemical cleaners in your home. I have recently started using ‘Enjo’ and although expensive and at times does take a little more work I feel the benefits from not needing to use surface sprays is totally worth it.
- Try eating organic. Non organic vegetables can often contain residue pesticides which although not directly discussed here can also be endocrine disruptors. Additionally, non organic meat can contain remnants of hormones and antibiotics given to the animals which then passes up the food chain to us.
- Limit handling til receipts!
- Stick as much as possible to unprocessed foods and avoid canned foods (unless you know that the lining of tins are BPA free).
- Being aware of the environment you are in. For example, trying to avoid places where you know lots of air freshener or scented candles are used or if you have laid new carpet, for example, ensure it has been aired out as much as possible before you move back in.
The bottom line
Although the evidence to say that phthalates negatively influences IVF outcomes is not yet conclusive, there does seem to be a growing body of evidence to say that they are very likely to have at least some impact. And although it will be near impossible to ever completely eliminate your exposure to phthalates, BPA and other environmental toxins, given that your IVF cycle is potentially the most important thing to ever happen to you and you want to do all you can to support its success it wouldn’t hurt to eliminate reduce your exposure as much as possible whilst still living life. This includes eating organic, reducing use of nail polish hair spray and especially fragranced cosmetics and minimising food that has been inside plastic (especially plastic that has been heated such as in a microwave) containers. You know, while living in the 21st century, juggling work and ultrasound appointments.
- Younglai, E, Holloway, A, Foster, W. (2005). Environmental and occupational factors affecting fertility and IVF success. Human Reproduction Update, 11 (1) 43–57, doi:10.1093/humupd/dmh055
- Ehrlich, S., Williams, P., Missmer, S., Flaws, J., Ye, X., Calafat, A., Petrozza, J., Wright, D. and Hauser, R. (2012). Urinary bisphenol A concentrations and early reproductive health outcomes among women undergoing IVF. Human Reproduction 27 (12) 3583–3592.
- Fujimoto, V., Kim, D., vom Saal, F., Lamb, J., Taylor, J. & Bloom, M. (2011) Serum unconjugated bisphenol A concentrations in women may adversely influence oocyte quality during in vitro fertilization. Fertility and Sterility 95 (5) 1816 – 1819
- Hauser, R., Gaskins, A,, Souter, I., Smith, K., Dodge, L., Ehrlich, S., Meeker, J., Calafat, A. and Williams, P. for the EARTH Study Team (2016). Urinary Phthalate Metabolite Concentrations and Reproductive Outcomes among Women Undergoing in Vitro Fertilization: Results from the EARTH Study. Environmental Health Perspectives 124 (6) 831- 839.
- Wu, H., Ashcraft, L., Whitcomb B., Rahil, T., Tougias, E., Sites, C. and Pilsner, J. (2017). Parental contributions to early embryo development: influences of urinary phthalate and phthalate alternatives among couples undergoing IVF treatment. Human Reproduction 32 (1) 65- 73.