Researchers from the reproductive biology group at Tallinn University of Technology and the Tartu-based company Celvia have described how DEHP, a chemical found in household products, can damage female fertility. The study was conducted in collaboration with the Pan-European FREIA consortium, and the results were published in the prestigious journal Environment International.
Phthalates are used worldwide in various household products such as food containers, toys, waterproof materials, as well as in cosmetics and medical products, because their properties help to make plastic items flexible and water-repellent. DEHP (diethylhexyl phthalate), one of these phthalates, is easily released from plastic and enters both the environment and our bodies. Since phthalates are found in both drinking water and dust, avoiding exposure to these chemicals is challenging. The ovaries of most women of reproductive age contain measurable amounts of DEHP, particularly in the follicle, which makes up the environment surrounding the human oocyte (the developing egg).
The use of DEHP, one of the most common phthalates, is banned in the European Union for household products and children's toys due to links to various health issues. However, DEHP is still allowed in medical items, such as blood storage bags and medical tubing.
The study examined samples from in vitro fertilization (IVF) patients in Estonia and Sweden and found that DEHP impacted the production of sex hormones. "We found that higher DEHP levels in the ovaries are associated with changes in sex hormone production, which could negatively affect a woman's fertility," explained the lead author, Inge Varik, from TalTech's reproductive biology group.
For the first time, the study also found a connection between DEHP and inflammatory processes in the ovary. According to Andres Salumets, chairman of Celvia and a co-author of the study, an excessive immune response can damage the support cells that produce sex hormones or the oocyte itself, which again jeopardizes female fertility.
In a previous research project, the same team showed that the ovaries of IVF patients with higher levels of DEHP were less responsive to fertility treatment. Agne Velthut-Meikas, head of TalTech’s reproductive biology research group and a co-author of both studies, noted: “IVF is one of the most accessible ways for infertile couples to have a biological child, but only about one in three procedures results in a live birth. The presence of chemicals in the ovary may further reduce the chances of success.”
The study emphasizes the need for better methods to assess the impact of chemicals on female fertility. Current animal testing methods do not provide sufficiently accurate assessments of chemical effects on women’s health.
References:
- Varik et al., https://doi.org/10.1016/j.envint.2024.108960
- Bellavia et al., https://doi.org/10.1016/j.envres.2022.114447