The vaginal microbiome

Before birth, a baby lives in a sterile environment in the womb (synonym: uterus). The baby’s passage through the birth canal, and subsequent first contacts with the outside world (skin-to-skin contact after birth, grooming, breastfeeding, cuddling…) lay the basis for the development of microbial ecosystems in various places in the human body, such as in the oral cavity, intestines, vagina and on the skin. Such a complex set of bacteria and other micro-organisms (yeasts, fungi, viruses, ...) in a specific environment is called a microbiome.

​

The vaginal microbiome is unique for every woman, but also dynamic over time. The composition varies under the influence of hormones (e.g. fluctuations in the menstrual cycle, pregnancy, hormonal contraception, menopause), vaginal blood loss, diet, lifestyle (e.g. smoking, exercise), chronic conditions (e.g. diabetes, inflammatory bowel disease, obesity), infection and medication (e.g. antibiotics), etc... In addition, genetic factors and ethnic background also play a role.

​

In women of reproductive age (from the first menstrual period until menopause), the vaginal microbiome consists mainly of lactobacilli. These “good” bacteria play an protective role in the resistance against infections and help to maintain a healthy vagina. Lactobacilli produce lactic acid, thereby creating an acidic environment, hydrogen peroxide (H2O2) and bacteria-killing substances (bacteriocins). Lactobacilli prevent the attachment of disease-causing (pathogenic) bacteria to vaginal epithelial cells and help our immune system to fight infections (immunomodulation). 

​

A disturbance of the vaginal microbiome, also called vaginal dysbiosis, is characterized by a very low number of "good" lactobacilli. This increases the risk of vaginal infections, as well as recurrence of infections after antibiotic treatment. A specific form of dysbiosis is bacterial vaginosis, in which there is an excess of anaerobic gut bacteria and very little to no lactobacilli in the vagina. This can cause symptoms of excessive, bad smelling vaginal discharge or irritation.