The Microbiome No One Checks: The Bugs that Live in the Uterus
A study out of the University of Washington has just shown that DNA from bacteria are present in 95% of uterine specimens at the time of hysterectomy. This refutes the long held theory that the uterus is sterile. By also looking at local tissue markers for infection, in most cases there was no inflammation although there were bacteria. Like in other conditions, presence of bacteria alone is not enough to determine that disease is present. The study then also refutes the theory that just bacterial presence in the uterus constitutes an infection. The thinking is that low levels of infection may be a relatively normal finding, just like low levels of bacteria on our skin, in the vagina, in the bladder, and in the urethra. Interestingly, the study also showed that there were different bacteria in the uterus than in the vagina, so there may be differences in why certain bacteria appear in certain places. The vagina and the uterus share many bacteria, including some of the healthy lactobacilli, but they do not always have the same bacteria. None the less, as important as bacterial testing is, when testing for infections it's always important to remember, clinical picture is as important as one test verses another test.
The Human Microbiome project shows that we carry the biggest mix of bugs in our mouth, and the fewest in the vagina and endometrium (inside of the uterus). Pelvic infections are due both to disruption of the healthy bacteria, as well as presence of abnormal bacteria.
The prevailing theory of pelvic infection, even those that eventually lead to infertility, miscarriage, tubal disease or pelvic pain, is that the result from an imbalance situation of the normal bacteria. In other words these infections are determined, by which bacteria, or so called, 'bad bacteria' make their way from the vagina, through the cervix, through the normally sterile uterine cavity, into the the Fallopian tubes, and cause infection. The resulting disease has been labeled pelvic inflammatory disease (PID), it may be acute or chronic.
Much more work has to be done to determine what is normal, how the colonies change in response to changing hormones, changing health, or diet. We don't yet know if the different bugs change from cycle to cycle or if they change during a single cycle, or in response to using contraception. We have shown that the bacteria in the vagina can normalize with the healing treatments of MonaLisa Touch therapy, but now we wonder if that therapy can in turn change the environment of the uterus for the better as well. All exciting areas of study!