Changes in Vaginal Microbiota in Pregnant Women with COVID-19 Increase Risk of Preterm Birth

A new study conducted by researchers at the Koç University Isbank Center for Infectious Diseases (KUISCID) reveals crucial data on the risk of preterm birth caused by the change in vaginal microbiota due to COVID-19. Research began in spring 2020 when the pandemic broke out and continued until vaccines became available. Although studies showing the effect of SARS-CoV-2 on preterm births have been highlighted by many health experts during the pandemic, this is the first research to focus on the cause of this link. That is why the study attracted a great deal of international attention worldwide. The results were published in the Journal of Medical Virology, one of the world’s most successful journals in this field.

Microbiome of the Vagina and its Importance

Vaginal microbiota refers to all microorganisms found in the female reproductive system. There are around 250 different types of bacteria in the vagina, as well as viruses, with the dominating lactobacilli. These bacteria protect the vagina and prevent pathogens from entering. They also produce lactic acid, which is critical to maintain the acidic pH of the vagina. If the number of lactobacilli decreases, the vaginal flora becomes unbalanced and bacterial vaginosis can develop. This is a pathological change in the vaginal microbiota, in which there is an increase in the occurrence of anaerobic bacterial species, while aerobic bacterial species decrease. Many women complain about grey discharge that can be frothy and has often an unpleasant fishy smell. Itching in the vaginal area and pain during sexual intercourse and urination are also possible symptoms. The multiplication of harmful organisms in the vagina entails risks, such as the risk of premature birth.

Microbiota Changed by 70 Percent

KUISCID Vice Director Prof. Füsun Can, Assoc. Prof. of Obstetrics and Gynecology at Koç University Faculty of Medicine and Director of Perinatology Clinic Ebru Çelik and Ph.D. Student Gülin Özcan, examined the connection between COVID-19 and the disruption of the balance of the vaginal microbiota. The aim was to clarify whether the virus disrupts the balance of beneficial and harmful bacteria when it affects the vaginal microbiota. Together with numerous institutes of the university, an interdisciplinary approach was carried out in a time of great risks, high maternal mortality rates and a lack of vaccines. The study continued despite the risk in the middle of the pandemic. Samples were taken from severe COVID-19 cases who were pregnant and treated at Koç University Hospital.

Vaginal swabs were also collected from a control group. The study found that the disruption in the balance of the vaginal microbiota persisted even after the illness, and there were significant differences in the amount of pathogenic bacteria between the infected and control groups. The researchers discover a 70 percent change in the microbiota.

Increased Risk of Preterm Birth

Additional results on vaginal damage showed strong evidence that microbiota changes are the main cause of the increased risk of preterm birth during COVID-19, which usually affects more of the respiratory organs. According to the experts, the results of the study indicate that the composition of the vaginal microbiota is adversely affected by COVID-19 and there is pronounced dysbiosis during active COVID-19 infection. Bacterial vaginosis is a possible reason for premature birth. Since there is evidence of the relationship between dysbiosis in the vaginal microbiota and preterm birth, it can be speculated that one of the mechanisms explaining the increased rate of COVID-19-associated preterm birth may be vaginal dysbiosis.

Overall, COVID-19 causes dysbiosis in the vaginal microbiota in pregnant women with a significant reduction in the abundance of Lactobacillus species. Based on these results, the research indicates that COVID-19 promotes unfavorable vaginal flora, which could be the underlying cause of the increased risk of adverse pregnancy outcomes such as preterm birth. These results raise clinically relevant questions about the use of microbiome-associated biomarkers as a risk assessment tool for preterm birth in pregnant women during COVID-19. New studies should be conducted to investigate possible methods of modifying the vaginal microbiota in pregnant women with COVID-19 infection to minimize the risk of adverse birth outcomes.

The results of this study are intended to raise awareness not only for the crucial role of vaccines, but also of the importance of vaginal microbiota and early treatment. Ebru Çelik points out that this process has also helped change people’s perceptions of a topic that was considered taboo in some regions. Vaginal examinations are still rarer than other systematic examinations and have yet to become mainstream among women around the world. The attention that has been drawn to the issue during the pandemic may be instrumental in reducing pregnancy risks in the future.