Influence of microplastics on fertility

There is no doubt that plastics change the way that we live in many aspects. From medical devices and tools to computers and cell phones, plastic compounds have made many of our possessions cheaper, lighter, safer, and stronger (1).

The first synthetic polymer was invented in 1869, however, it was almost 100 years later, in the 1960s, when the first plastic debris was observed in the oceans and the awareness of environmental problems caused by plastics increased (1). For decades the disposal of plastic compounds hasn't been the proper one, generating an enormous amount of plastic pollution accumulated in almost every place and environment on earth (2). In the last few decades, special attention has been given to microplastics (MP) and their effects on the environment and specifically on human health. MP are plastic debris of less than 5 mm in length (about the size of a sesame seed), and it has been suggested that due to their nature and characteristics, they may concentrate hazardous compounds such as heavy metals or pollutants, and carry them into the environment and living organisms (3). The effects of MP on health are still under research, but there’s evidence pointing to the fact that plastic debris in micro and nano range can act as endocrine-disrupting chemicals (EDCs) (4). EDCs are able to mimic, block or interfere with the activity of naturally produced steroid hormones like androgens, oestrogens, and progestogens, and affect many metabolic pathways, such as fertility, sperm quality, abnormalities in sex organs, endometriosis, early puberty, among others (5).

Between 1973 and 2011 the sperm concentration of men from Europe, North America, Australia, and New Zealand decreased by 52.4%, while the sperm count by 59.3%. The causes of this continuing decline are not completely explained yet, but it has been attributed in part to the EDC and other environmental factors (stress, smoking, diet, etc.) (6). For example, Bisphenol A (BPA), an EDC that is used for the production of some plastics, can affect spermatogenesis and sperm quality. BPA induces overall cell damage within the testis, resulting in cell death and affecting sperm’s motility, morphology, and concentration (4).

Dr. Shanna Swan, professor of environmental medicine and public health at Mount Sinai school of medicine in New York City, has a long career and hundreds of publications studying fertility trends. Part of her job has been dedicated to making awareness about the role of chemicals in the rising number of sub-fertility or reproductive problems. Dr. Swan and colleagues have found that rapidly dividing cells (e.g during foetus formation) are more sensitive to EDC, and the hits continue through childhood, adolescence, and adulthood. This results not only in lower sperm count but also decrease libido, increased risk of early puberty, premature ovarian failure, miscarriage, and premature birth. She claims that all this could generate that by 2045 most couples may have to use assisted reproductive techniques in order to have a baby (7).

Definitely PM pollution is and will be a great ecological challenge. More studies, awareness and efforts are needed from the chemical industry to produce non-hormonal active compounds. If you are planning a pregnancy, prefer unprocessed foods, avoid putting plastic containers in the microwave as well as the use of Teflon. Also, use personal care products that do not contain compounds such as phthalates (7). Certifications such as Made Safe and EWG Verified can be a good guide to choosing non-toxic beauty products.

References: 1.Science History Institute. History and Future of Plastics https://www.sciencehistory.org/the-history-and-future-of-plastics#:~:text=Plastics%20made%20possible%20the%20development,in%20heating%20and%20in%20transportation.

2.LMU. Microplastics and fertility. https://www.genzentrum.uni-muenchen.de/research-groups/ferraz/research/mircroplastics/index.html

3.National Ocean Service. What are microplastics? https://oceanservice.noaa.gov/facts/microplastics.html

4.D'Angelo, S., & Meccariello, R. (2021). Microplastics: A Threat for Male Fertility. International journal of environmental research and public health, 18(5), 2392. https://doi.org/10.3390/ijerph18052392

5.Endocrine Society. Endocrine-Disrupting Chemicals https://www.endocrine.org/topics/edc

6.Levine H, Jørgensen N, Martino-Andrade A, Mendiola J, Weksler-Derri D, Mindlis I, Pinotti R, Swan SH. Temporal trends in sperm count: a systematic review and meta-regression analysis. Hum Reprod Update. 2017 Nov 1;23(6):646-659. doi: 10.1093/humupd/dmx022. PMID: 28981654; PMCID: PMC6455044.

7.The Guardian. Corbyn, Z. Interview: Shanna Swan: 'Most couples may have to use assisted reproduction by 2045”. https://www.theguardian.com/society/2021/mar/28/shanna-swan-fertility-reproduction-count-down