A team of doctors in Copenhagen has successfully implemented an “artificial ovary” in mouse trials. The ovary was constructed out of human tissue, and may someday be able to help women who’ve been through treatments that can affect fertility, such as chemotherapy. As The Guardian reports, these artificial ovaries could also help women with other conditions that require fertility-harming treatment, like multiple sclerosis and beta thalassemia.

Currently, women have the option of freezing their own ovarian tissue before receiving treatments that can compromise ovarian function. This tissue is then thawed and re-implanted after they’ve undergone treatment. After having their ovarian tissue reinserted, women are often able to get pregnant naturally, without the use of IVF.

But the existing procedure is risky for women with a history of leukemia or ovarian cancer, because in these cases, the cancer invades the ovarian tissue. In such cases, if the frozen ovarian tissue is returned after treatment, the woman is put at risk of relapsing.

According to the team of Copenhagen doctors, implanting bioengineered ovarian tissue would be a safer option. The doctors were able to isolate follicles from frozen ovarian tissue donated by women who’d had it removed prior to treatment. Follicles are the tiny sacs inside the ovary that contain the eggs. The doctors were also able to strip the frozen ovarian tissue of cells, or “decellularize” it, and use the remaining matter to create a sort of “scaffolding” around the follicles, mimicking a natural ovary.

The decellularization process would also remove any potential cancer cells, which is why there would be no risk of cancer even if the original frozen tissue contained cancerous cells. And because the process does not require access to a woman’s own ovarian tissue, it could also be used in patients who have gone through early menopause.

Susanne Pors, one of the doctors leading the study, explained that the doctors had been able to successfully implant a lab-made ovary containing 20 human follicles into a mouse. Five follicles were able to survive for at least three weeks, and even developed blood vessels in the mouse to support the implanted ovary.

While this is undoubtedly positive news, it may be some time yet before the new process can be help human women. “This is the first proof that we can actually support these egg cells. It’s an important step along the road,” Pors told The Guardian. “But it will be many years before we can put this into a woman.” According to Pors, it could take another five to 10 years before women can have access to this technology.