Women's fallopian tubes and ovaries were once thought to be free of bacteria, but a small new study finds that these microorganisms do live naturally in this part of the reproductive tract.

What's more, the findings suggest that women with ovarian cancer may have different, more harmful bacteria in their fallopian tubes and ovaries, but much more research is needed to confirm this idea, the researchers said.

In the study, the researchers analyzed tissue samples from 25 women who had been through menopause and were undergoing surgery to have their uterus, fallopian tubes or ovaries removed. Some of the patients had ovarian cancer, and some did not.

The samples were obtained under sterile conditions, and were immediately frozen in liquid nitrogen to ensure that they weren't contaminated with bacteria during collection, said study co-author Dr. Wendy Brewster, director of the University of North Carolina at Chapel Hill's Center for Women's Health Research. The researchers used genetic sequencing to identify the types of bacteria in the fallopian tubes and ovaries.

The results showed that there were bacteria in this part of the reproductive tract, and that there were different types of bacteria living in the fallopian tubes versus in the ovaries. [7 Facts Women (And Men) Should Know About the Vagina]

"We found that the upper reproductive tract is not sterile, and that bacteria do actually exist there," study co-author Temitope Keku, a professor of medicine at the University of North Carolina at Chapel Hill, said in a statement.

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The study also suggested that there were differences in the bacteria in the women with ovarian cancer compared with the bacteria in the women without cancer. However, it's possible that these differences were due to chance, and more research is needed to confirm the finding and to investigate whether the bacteria in these sites could affect women's cancer risk, the researchers said. It's possible that the changes in bacteria happened after the patients developed cancer, the researchers noted.

The new study will be presented today (June 6) at the American Society of Clinical Oncology's (ASCO) annual meeting in Chicago. It has not yet been published in a scientific journal.

To confirm their findings, the researchers plan to repeat their study in a larger group of women, Brewster said.

The study adds to other recent evidence that the fallopian tubes and ovaries are not sterile. A study published in the May 2015 issue of the journal Obstetrics & Gynecology also found bacterial colonization in the upper parts of the female reproductive tract.

Original article on Live Science.

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