Probiotics in Vaginal Health

Written by Dr Nada Millen, Head of Science and Innovation at Amelia

MPharm, MSci, PhD with over 15 years of research experience.

Reviewed by Associate Professor Leo Leader

FRANZCOG, FRCOG, one of the most experienced Obstetricians and Gynaecologists in Sydney, who has been practicing and teaching for over 35 years. He held appointments as a Senior Visiting Medical Officer at the Royal Hospital for Women and Prince of Wales Hospital in Sydney.

Probiotics in Vaginal Health

Vaginal microbiota was discovered as a distinct microbiome containing Lactobacillus species in 1891 by gynaecologist Alber Döderlein. Since then, there has been a lot of research done trying to understand vaginal microbiome dynamics and the role of probiotics in vaginal health.

There are a few principles that could help determine which probiotic product would be the most beneficial in improving vaginal health:

1. Right strain.

Lactobacillus species do not have the same ability to colonise vaginal environment as well as produce lactic acid, hydrogen peroxide and other bacteriocins. Even different strains within the same species have different properties. Therefore, it is important to use the specific strain that has been characterised and tested for the best performance in vaginal environment.

L. crispatus and L. gasseri are the most beneficial vaginal probiotic species, present in 2/3 of vaginas across the world.

L. rhamnosus, GR-1™ and L. reuteri, RC-14™ have been extensively researched in the last 20 years in more than 30 clinical trials related to vaginal and urinary health. Those strains have been tested in vitro as well as in clinical settings, on healthy women and patients with BV and VVC, on both pre-menopausal and menopausal women.

The relevant clinical trials are listed below:

Reid G, Charbonneau D, Erb J, Kochanowski B, Beuerman D, Poehner R, Bruce AW. Oral use of Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women. FEMS Immunol Med Microbiol. 2003 Mar 20;35(2):131-4
Reid G, Burton J, Hammond JA, Bruce AW. Nucleic acid-based diagnosis of bacterial vaginosis and improved management using probiotic lactobacilli. J Med Food. 2004 Summer;7(2):223-8.
Petricevic L, Unger FM, Viernstein H, Kiss H. Randomized, double-blind, placebo-controlled study of oral lactobacilli to improve the vaginal flora of postmenopausal women. Eur J Obstet Gynecol Reprod Biol. 2008 Nov;141(1):54-7
Reid G, Beuerman D, Heinemann C, Bruce AW. Probiotic Lactobacillus dose required to restore and maintain a normal vaginal flora. FEMS Immunol Med Microbiol. 2001 Dec;32(1):37-41
Yang S, Reid G, Challis JRG, Gloor GB, Asztalos E, Money D, Seney S, Bocking AD. Effect of Oral Probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on the Vaginal Microbiota, Cytokines and Chemokines in Pregnant Women. Nutrients. 2020 Jan 30;12(2):368.
Husain S, Allotey J, Drymoussi Z, Wilks M, Fernandez-Felix BM, Whiley A, Dodds J, Thangaratinam S, McCourt C, Prosdocimi EM, Wade WG, de Tejada BM, Zamora J, Khan K, Millar M. Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis. BJOG. 2020 Jan;127(2):275-284.
Gille C, Böer B, Marschal M, Urschitz MS, Heinecke V, Hund V, Speidel S, Tarnow I, Mylonas I, Franz A, Engel C, Poets CF. Effect of probiotics on vaginal health in pregnancy. EFFPRO, a randomized controlled trial. Am J Obstet Gynecol. 2016 Nov;215(5):608.e1-608.e7
Reid G, Bruce AW, Fraser N, Heinemann C, Owen J, Henning B. Oral probiotics can resolve urogenital infections. FEMS Immunol Med Microbiol. 2001 Feb;30(1):49-52.

2. Right dose.

The vagina is a relatively small organ, on average 10 cm long, producing 1-4 ml of vaginal discharge per day. The availability of space and nutrients available to microbiome in this environment is limited, which is why having higher concentration of vaginal probiotics does not necessarily yield better results. The optimal dose of probiotic organisms for beneficial health effect is determined by clinical trials. Most of the studies have health benefit achieved using dose in the range of 10⁹ CFU/day. This dose is not present in products which are not in a medical category (manufactured and tested for the quality and exact dose assurance), such as different food products (e.g., yoghurt).

3. Right route of administration.

Oral probiotics are currently employed for vaginal health due to their convenient administration. However, vaginally applied probiotics have been demonstrated to be more effective.

Advantages of vaginally applied probiotics:

Targeted delivery
Higher dose. Orally administered probiotics must withstand the challenges of the gastrointestinal environment.
Rapid action which is crucial for prompt relief from discomfort and unpleasant symptoms.
Reduced application time. Vaginal probiotics are applied over 5-10 days, while oral probiotics need to be applied for minimum of 30 days.
Vaginal colonization opportunities maximized.