Microplastics Unveiled: The Silent Threat to Fertility

12 Feb

Microplastics are environmental pollutants generated when plastic materials (from clothes, bottles, tires etc.) break down and fragment into a size ≤5 mm. These particles are ingested or inhaled but cannot be digested or degraded. Let’s delve into the relationship between microplastics and fertility, exploring the scientific findings, potential risks, and ways to mitigate this invisible threat to reproductive health.

Microplastics (MPs) are endocrine disruptors. This means they alter hormone production, release, transport, metabolism, and elimination and therefore, both male and female reproductive systems. MPs are carriers of contaminants such as ions, toxic heavy metals, and hydrophobic organic compounds which, if ingested regularly, can have serious health implications.

The average person who drinks three cups of coffee a day, in paper cups, ingests around 75,000 particles and just one surface crack on a Teflon-coated pan can release about 9,100 plastic particles. As evidence of this exposure, MPs have been detected in blood, urine, faeces, and breast milk. Further, microplastic accumulation has been identified organs including the lungs, colon, and spleen. More recently, accumulation was observed for the first time in the human placenta in a 2021 study, raising concerns related to the consequences of these contaminants on the health of pregnancies and babies. In a 2022 study, they were linked to reduce foetal growth in pregnancy (birth weight, head circumference and length).

Effects on reproductive health

Sperm quality
It is interesting to note that the exponential rise in global plastic production coincides with population-wide decline in human sperm production which appears to be accelerating since 2000. It is postulated that by 2045, if the current global sperm count trend continues, it will reach zero.
Male fertility, foetal health and the long-term health of offspring are dependent on the programming events that occur during spermatogenesis which are influenced by the environment. These delicate processes can be disrupted by exposures to various testicular toxicants (phthalates and BPA) linked to MPs.
This can impair spermatogenesis, sperm development, reduce sperm quality, and compromise fertility.
Female fertility
MPs have been found in uterine tissue including within growing follicles (developing eggs). These concerns are particularly heightened considering the developmental origins of health and disease (DOHaD) framework, which postulates that in utero exposure can programme the lifelong health of the offspring.
They have been linked to circulating hormone levels reductions in the circulating concentrations of estradiol (E2) and anti-mullerian hormone (AMH), and increased concentrations of LH, follicle stimulating hormone (FSH) and testosterone.
MPs have also been linked to decreased oocyte function, oxidative stress, and DNA damage.