Health Science Reviews

By Aluwani Nemutavhani

Can you review a Netflix series by watching only a single episode? Absolutely not, but
that’s exactly how most scientists have studied the vaginal microbiome. The vaginal
microbiome includes microorganisms which naturally live in the vagina, such as
viruses, bacteria, and bacteriophages. Most researchers have studied this from a single
time point, but in reality, the vaginal microbiome changes daily, influenced by
menstruation, stress, and sexual activity. Vaginal microbiota and its environment can
impact women’s fertility and reproductive health. For example, around one-third of
women worldwide are affected by bacterial vaginosis (BV).

In this study, the researchers are trying to study how the vaginal microbiome changes
daily over time, more especially during the menstrual cycle. They are also trying to find
out if there are different patterns or types of microbiome dynamics among women.

The study was carried out in two parts. In the pilot study, 15 women collected daily
vagina swabs for 42 days. They used 16S rRNA sequencing to identify different bacteria
present, this was to test the idea that they could track the vaginal microbiome. For the
main study, 49 women collected daily swabs across their menstrual cycles. Instead
of just looking at bacteria, this time they went deeper using shotgun metagenomic
sequencing to examine bacteria, viruses (such as bacteriophages), and their genes. Advanced tools like VALODY were used to classify women based on how stable or unstable their vaginal microbiomes were across time.

They discovered four Vaginal Community Dynamics (VCDs), namely VCD1-constant
eubiotic, VCD2-menses associated dysbiotic, VCD3-unstable and VCD4-constant
dysbiotic. These categories showed how some women’s microbiomes stay stable while
others shift during menstruation. The study also found that viruses and bacterial genes
play a role in communities being stable or unstable.

This study changes our perspective on how we think about vaginal health. There is no
perfect vaginal microbiome, and these daily shifts are natural. By understanding the
different community dynamics, we can better predict and prevent vaginal health
problems. Personally, I think vaginal health is still one of the misunderstood areas in
reproductive science. We need more researchers to focus on this area, the vaginal
microbiome could be holding answers to deeper questions that relate to menstrual
pain, Polycystic Ovary Syndrome (PCOS), and so much more.

References:

• Hugerth, L. W., Krog, M. C., Vomstein, K., Du, J., Bashir, Z., Kaldhusdal, V.,
  Fransson, E., Engstrand, L., Nielsen, H. S., & Schuppe-Koistinen, I. (2024).
  Defining Vaginal Community Dynamics: daily microbiome transitions, the
  role of menstruation, bacteriophages, and bacterial genes. Microbiome,
  12(1). https://doi.org/ARTN 15310.1186/s40168-024-01870-5