Vaginal Flora Linked To Fertility

Kathy Wheddon Nutritional Therapist DipION

We all understand the importance of having healthy probiotic colonies in the gut, but up until now the health of the ‘intimate’ flora has often been greatly overlooked. A recent Danish study 1 published in the ‘Journal of Human Reproduction’ reviewed potential links between Bacterial Vaginosis and IVF success rates. This study raises the question of whether it is possible that an imbalanced vaginal flora can have more far reaching consequences than simply causing infection and discomfort?

Women with child
One in seven couples in the UK experience difficulties conceiving

The study group was composed of 130 infertile women who were undergoing IVF fertility treatment at two different fertility clinics in Denmark. Each of the women was given vaginal swabs at the beginning of the study, and these swabs were analysed for bacterial numbers and species.

36 out of the 130 women (representing 28% of the study group) were found to have vaginal swabs showing ‘abnormal’ vaginal flora. ‘Abnormal vaginal flora’ was defined as having high levels of either of the pathogenic bacteria species G. vaginalis or A. vaginae. 27 of these 36 cases of ‘abnormal’ flora were then classified (using the Nugent’s criteria) as being Bacterial Vaginosis (BV).

Unfortunately, some of the study participants dropped out along the way, so only 84 women completed the study (this group of 84 women included only 22 of the 27 identified BV sufferers). The results from the cohort study were, that 29 out of the 84 women had a successful IVF result, ending in pregnancy (35% success rate), however only 2 out of the 22 BV sufferers became pregnant, representing only a 9% success rate.

What is the significance of this?

The results of this study show a big difference in pregnancy success rates between the BV group and the non-BV group (9% as compared to 35%).

Whilst the study size was small and undoubtedly necessitates further research, I feel that the results are still encouraging. Infertility rates are on the rise, and according to NHS figures 2, more than 1 in 7 couples now have difficulties conceiving. This causes both considerable distress to the couples, and potentially expense (if they decide to opt for IVF treatment).

More and more often women are looking to complimentary health practices such as acupuncture, reflexology and nutritional therapy in order to boost their chances of conceiving naturally, all of which I am hugely in favour of. The human body is capable of amazing things if we just give it the correct ‘building blocks’ and nutrition to do so.

Eliminating BV (or correcting vaginal dysbiosis) would seem like an obvious way to rule out one possible causative factor in infertility. Vaginal flora should be made up of 95% Lactobacilli species. These bacteria secrete lactic acid which keeps the pH of the urogenital area within its healthy range. Using soaps, shower gels and douches causes the vagina to become too alkaline, and an alkaline environment favours the growth of pathogenic bacteria, and contributes to vaginal dysbiosis. To find out how to keep the vaginal flora healthy, read The Vaginal Flora: What Every Woman Should Know.

Two species of bacteria (Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1®) are known to colonise the intimate area, as they were isolated originally from the vaginas of healthy women. Once they have colonised the vaginal mucosa these strains of bacteria help to maintain a healthy pH, whilst competing for space and nutrients with any pathogenic strains of bacteria that have taken up residence. Healthcare professionals can read more about the research into Lactobacillus reuteri RC-14® and Lactobacillus rhamnosus GR-1® by visiting their entries on the Probiotics Database.

You might also be interested in:
Getting pregnant: could probiotics help?
Which Probiotics are best for women?


  1. Abnormal vaginal microbiota may be associated with poor reproductive outcomes: A prospective study in IVF patients. T. Haahr, J.S. Jensen, L. Thomsen, L. Duus, K. Rygaard and P. Humaidan. Faculty of Health, Aarhus University and the Fertility Clinic, Skive Regional Hospital, Skive, Denmark.