Current endometriosis treatment relies on hormonal contraception as well as invasive surgeries, with no definitive treatment. The chances of endometriosis recurrence after surgery remain at 50% within 5 years (Yang et al., 2020), and hormonal therapies can cause unwanted side effects, with symptoms that return when treatment stops. It is clear that the need for novel and targeted therapies to prevent endometriosis development and recurrence is vital. This is exactly what Anthis et al. (2024) tackled in their research.

The researchers sought to introduce a new approach to endometriosis treatment. Their solution? Mechanical contraception using hydrogel implants. Instead of altering hormones, their approach physically blocks the fallopian tubes using a removable hydrogel. Anthis et al. designed this implant that could be placed in the fallopian tubes in order to prevent endometrial cells from travelling through the fallopian tubes towards the pelvic cavity, while also preventing sperm passage for contraception.

This practice relies on the theory of retrograde menstruation, believed to be one of the leading theories proposed to explain the development of endometriosis. This is one of the oldest theories developed by Sampson almost a century ago. It states that endometrial cells can travel backwards through the fallopian tubes into the pelvic cavity, where some cells may survive and contribute to endometriotic lesions (Lamceva, Uljanovs and Strumfa, 2023). The causes of endometriosis still remain uncertain, but retrograde menstruation continues to be an important theory in endometriosis research. Therefore, the researchers asked a surprisingly simple question: what if you physically blocked that route?

Anthis et al. developed two implantable hydrogels: a photolabile gel (PL), designed to break down when exposed to light, and a thiol-degradable gel (TD), designed to break down when exposed to a glutathione solution (a natural molecule found in the body (Labarrere and Kassab, 2022)). The researchers designed the hydrogels to be inserted through the uterus using a clinical hysteroscope (a small camera) and positioned at the proximal opening of the fallopian tubes, without the need for surgery. Once in position, the hydrogel would then swell to occlude the fallopian tube, creating a barrier for cell passage.

The researchers then tested different aspects of the hydrogel system using mechanical experiments, laboratory models and an in vivo porcine (pig) model. The hydrogels withstood pressures considerably higher (with burst pressures of around 255–558 mmHg) than normal abdominal pressures (around 95 mmHg), suggesting that they could remain securely in place under physiological conditions. The hydrogels showed negligible cytotoxicity, meaning that they caused very little toxicity toward cells in a laboratory setting (Thermofisher.com, 2026). In the porcine model, an implanted hydrogel was successfully recovered after 3 weeks, with no detectable adverse effects on the surrounding fallopian tube. Finally, the researchers created an in vitro (outside a living organism, in a laboratory setting (Jain et al., 2018)) model to test whether the hydrogel could actually block endometrial-cell passage. Endometrial cells could travel through unobstructed fallopian tubes, but the hydrogel prevented them from passing through the blocked tubes. The hydrogel also prevented the passage of sperm cells, supporting its potential use as a non-hormonal contraceptive.

Together, these findings demonstrate the potential of hydrogel implants as a reversible way of physically blocking the fallopian tubes, raising the possibility of using the same technology for both non-hormonal contraception and endometriosis prevention. One potential application may lie in the prevention of new lesion formation or recurrence following surgery, which is still a large issue regarding treatment. Importantly, the researchers did not demonstrate that blocking endometrial cell passage actually prevents endometriosis from developing or recurring. The endometriosis experiment demonstrated cell blockage in vitro, not disease prevention in animals or humans.

There is also a much bigger question: retrograde menstruation alone cannot fully explain endometriosis. The disease is complex, with genetic, immune and hormonal factors also thought to contribute to its development. If different mechanisms drive disease in different patients, physically blocking the fallopian tubes may not prevent every form of endometriosis. Therefore, whether these hydrogel implants could actually prevent endometriosis development or recurrence remains unknown.

Additionally, the researchers mentioned that long-term studies will also need to determine whether the fallopian tubes remain healthy after prolonged implantation and removal, and importantly, whether natural fertility can be fully restored afterwards. The removal process also requires further optimisation, and complete degradation was achieved in two of the three cases with the TD gel, while the PL showed substantial degradation but did not completely degrade in the experiments. Finally, Anthis et al. emphasise the need for further in vivo (within a living organism (Merriam-Webster, 2020)) research before this technology can progress towards clinical trials.

What do you think? Could hydrogel implants one day help prevent the recurrence of endometriosis?

References

  1. Anthis, A.H.C., Kilchenmann, S., Murdeu, M., LeValley, P.J., Wolf, M., Meyer, C., Cipolato, O., Tibbitt, M.W., Rosendorf, J., Liska, V., Rduch, T. and Herrmann, I.K. (2024). Reversible Mechanical Contraception and Endometriosis Treatment Using Stimuli‐Responsive Hydrogels. Advanced Materials, 36(23). doi:10.1002/adma.202310301.

  2. Yang, F., Liu, B., Xu, L. and Liu, H. (2020). Age at surgery and recurrence of ovarian endometrioma after conservative surgery: a meta-analysis including 3125 patients. Archives of Gynecology and Obstetrics, 302(1), pp.23–30. doi:10.1007/s00404-020-05586-3.

  3. Lamceva, J., Uljanovs, R. and Strumfa, I. (2023). The Main Theories on the Pathogenesis of Endometriosis. International Journal of Molecular Sciences, 24(5), p.4254. doi:10.3390/ijms24054254.

  4. Labarrere, C.A. and Kassab, G.S. (2022). Glutathione: A Samsonian life-sustaining small molecule that protects against oxidative stress, ageing and damaging inflammation. Frontiers in Nutrition, 9. doi:10.3389/fnut.2022.1007816.

  5. Thermofisher.com. (2026). Cytotoxicity Assays | Thermo Fisher Scientific - US. [online] Available at: https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-viability-and-regulation/cytotoxicity.html [Accessed 7 Oct. 2026].

  6. Jain, A.K., Singh, D., Dubey, K., Maurya, R., Mittal, S. and Pandey, A.K. (2018). Models and Methods for In Vitro Toxicity. In Vitro Toxicology, pp.45–65. doi:10.1016/b978-0-12-804667-8.00003-1.

  7. Merriam-Webster (2020). Definition of IN VIVO. [online] Merriam-webster.com. Available at: https://www.merriam-webster.com/dictionary/in%20vivo [Accessed 7 Oct. 2026].