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Optimize your vaginal microbiome for fertility

When it comes to improving fertility, one key factor that we must consider is the health of the vaginal and uterine microbiome. It makes sense when we consider that the health of the uterus for implantation is crucial for a successful pregnancy, yet it's so often overlooked. In this article I outline what you need to know about your vaginal microbiome to boost your chances of fertility success.

What is the Vaginal Microbiome?

We hear alot about the gut microbiome, but what's the vaginal microbiome? The word microbiome refers to a community of microbes which may include bacteria, viruses and fungi, that exists within and on our bodies, from your gut, to your skin, to breastmilk and yes, the vagina!

The vaginal microbiome is where a community of microbes live from the cervix to the external anatomy of the vulva. It's a complex little ecosystem made up of more than 200 bacterial species. These species are unique to each and every one of us, and may be influenced by:

  • Genes

  • Ethnicity

  • Environment

  • Fluctuates over your menstrual cycle

  • Certain hygiene practices like using powders, deodorants or douching

  • Sexual habits.

One type of bacteria within the vaginal microbiome is called Lactobacillus (the one you always see advertised on the back of yoghurt containers!). These bacteria maintain an acidic environment (pH 3.5-4.5) that protects against infections and can potentially support the prevention of sexually transmitted infections, maintain healthy mucus production, and help care for a healthy pregnancy and vaginal delivery (1).

Why is the Vaginal Microbiome Important for Fertility?

Not only is a healthy vaginal microbiome more comfortable to live with (more on that niggly vaginal thrush soon!), it can also play a big part in our chances of conception. Research has found many benefits for fertility including the following:

  • Protection Against Infections: Lactobacilli produce lactic acid and hydrogen peroxide, which inhibit the growth of pathogenic bacteria (2).

  • Support Sperm Health: An optimal vaginal environment ensures that sperm can survive and travel through the cervix to fertilize an egg (3).

  • Enhancement of Implantation: A healthy uterine microbiome is essential for creating a receptive environment for embryo implantation (4).

There is also potential that certain conditions affecting the vaginal microbiome might be impacting on your chances of conceiving.

Bacterial Vaginosis (BV)

BV occurs when there is an overgrowth of anaerobic bacteria and a reduction in Lactobacillus. BV has been linked to increased risks of pelvic inflammatory disease, miscarriage, and preterm birth (5). You may have BV without any symptoms so it could be worth getting tested- it just takes a simple swab to check your vaginal bacterial balance (6). If you test positive for BV, often the treatment is antibiotics- after which its recommended to opt in some probiotics to restore a healthy balance.


Ureaplasma is a type of bacteria that can inhabit the reproductive tract without causing symptoms. However, it has been associated with infertility, miscarriage, and preterm labor (8). This is another one you can have a simple test for with your GP and the treatment is usually antibiotics.

What about vaginal thrush?

How can we discuss the vaginal microbiome without mentioning the dreaded thrush?! This seriously uncomfortable yet common condition is caused by an overgrowth of the otherwise normal Candida fungus. It can cause itching, unpleasant discharge and inflammation.

So far there are no studies linking thrush with fertility directly but there are some suggestions on ways that you can alter your diet and lifestyle to reduce your chances of developing thrush.

  • Reduce Sugar Intake: High sugar diets can promote yeast growth.

  • Add in Probiotic Foods: Yogurt, kefir, and fermented foods can help maintain a healthy balance of bacteria. Be mindful though that many fermented foods aren't pregnancy safe so a great probiotic rich yoghurt could be your best bet in pregnancy!

  • Supplements: Probiotic supplements containing Lactobacillus rhamnosus and Lactobacillus reuteri have been shown to help prevent yeast infections (10). These specific strains are important as not all probiotics contain the same strains! Make sure to check.

What can you do to improve your vaginal microbiome?

Thankfully there are many things that we can alter with our nutrition to boost the health of our microbiome! My top tips are:

  • Incorporate more prebiotic rich foods. Prebiotics are non-digestible fibers that feed beneficial bacteria. Foods rich in prebiotics include:

  • Garlic

  • Onions

  • Asparagus

  • Bananas

  • Whole grains (13)

  • Incorporate more probiotic rich foods (and potentially supplements) into the diet. Fermented foods every day is amazing, but during pregnancy can be high risk. Once you fall pregnant make sure to stick to food-safety approved probiotic rich foods like yoghurt and just make sure you've optimised your microbiome well in advance!

  • Probiotic supplements are a way to introduce more beneficial bacteria to the microbiome. It's important however to make sure that an effective strain is used and they're taken in conjunction with a prebiotic fibre rich diet (otherwise the effectiveness can be limited). Some effective strains include:

    • Lactobacillus rhamnosus: Supports vaginal health and prevents infections (11).

    • Lactobacillus reuteri: Enhances the immune response and helps maintain a balanced microbiome (12).

Just be mindful that it's important to talk with your healthcare provider before starting any new supplements, and to note that probiotics during pregnancy have been associated with higher risk of preeclampsia so should be avoided until around 34 weeks.


Improving your vaginal microbiome through food and potentially getting some tests done to rule out problems is a simple way to boost your fertility naturally. If you are interested in learning more about nutrition for fertility and the most common fertility mistakes to avoid then make sure to tune in for my FREE fertility nutrition masterclass. I cover the top 5 mistakes that you could be making for fertility and what to do instead! I also talk you through my step by step process to leaving absolutely no stone unturned when it comes to improving your nutrition for optimal fertility. Click here to register and watch right now.


  1. Ravel J, Gajer P, Abdo Z, et al. Vaginal microbiome of reproductive-age women. Proc Natl Acad Sci U S A. 2011 Mar 15;108 Suppl 1:4680-7.

  2. Boris S, Barbes C. Role played by lactobacilli in controlling the population of vaginal pathogens. Microbes Infect. 2000 Apr;2(5):543-6.

  3. Donnez J, Donnez O, Dolmans MM. Introduction: Fertility preservation in women. Nat Rev Endocrinol. 2017 Dec;13(12):695-705.

  4. Moreno I, Codoñer FM, Vilella F, et al. Evidence that the endometrial microbiota has an effect on implantation success or failure. Am J Obstet Gynecol. 2016 Jun;215(6):684-703.

  5. Bradshaw CS, Brotman RM. Making inroads into improving treatment of bacterial vaginosis—striving for long-term cure. BMC Infect Dis. 2015 Aug 25;15:292.

  6. Sobel JD. Bacterial vaginosis. Annu Rev Med. 2000;51:349-56.

  7. Reid G, Burton J. Use of Lactobacillus to prevent infection by pathogenic bacteria. Microbes Infect. 2002 Mar;4(3):319-24.

  8. Taylor-Robinson D, Lamont RF. Mycoplasmas in pregnancy. BJOG. 2011 Apr;118(5):164-74.

  9. Waites KB, Katz B, Schelonka RL. Mycoplasmas and Ureaplasmas as neonatal pathogens. Clin Microbiol Rev. 2005 Oct;18(4):757-89.

  10. Martinez RC, Franceschini SA, Patta MC, et al. Improved cure of bacterial vaginosis with single-dose of tinidazole (2 g), Lactobacillus rhamnosus GR-1, and Lactobacillus reuteri RC-14: a randomized, double-blind, placebo-controlled trial. Can J Microbiol. 2009 Mar;55(2):133-8.

  11. Reid G, Charbonneau D, Erb J, et al. Oral use of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women. FEMS Immunol Med Microbiol. 2003 Aug 15;35(2):131-4.

  12. Mack DR, Ahrne S, Hyde L, et al. Extracellular MUC3 mucin secretion follows adherence of Lactobacillus strains to intestinal epithelial cells in vitro. Gut. 2003 Jul;52(7):827-33.

  13. Gibson GR, Roberfroid MB. Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. J Nutr. 1995 Jun;125(6):1401-12.


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