Lactobacillus Plantarum for Vaginal Health? What the Research Says

study PMID: 40679696

Quick Summary: Research on sheep shows that Lactobacillus plantarum (a type of probiotic) may help improve vaginal health and pregnancy rates in ewes. The study found that it reduced certain types of vaginal discharge and didn't cause any harm.

Can Probiotics Help Vaginal Health?

This study looked at how Lactobacillus plantarum (LAC), a beneficial bacteria, and its cell-free supernatant (CFS) affected the vaginal health and ability to get pregnant in sheep. The researchers found that LAC and CFS didn't cause any negative health effects. They also saw that LAC helped reduce a specific type of vaginal discharge.

Study Details

Who was studied: 196 Merino ewes (female sheep)

How long: The study lasted for 14 days.

What they took: The sheep were given either:

Lactobacillus plantarum (LAC)
Cell-free supernatant (CFS) of Lactobacillus plantarum
A hormone treatment (FGA or MPA) to help with breeding

What This Means For You

For sheep: This research suggests that Lactobacillus plantarum might be a helpful, non-antibiotic way to support vaginal health and improve pregnancy rates in sheep.

For humans: While this study was done on sheep, it adds to the growing body of research on probiotics and vaginal health. More research is needed to see if these findings apply to humans.

Study Limitations

Sheep only: This study was only done on sheep, so we can't be sure if the results would be the same for humans.

Dosage unknown: The exact amount of Lactobacillus plantarum used wasn't specified, making it hard to replicate the study.

Short-term study: The study only looked at the effects for 14 days, so we don't know if the benefits would last longer.

Key Findings

This 2025 study found that intravaginal administration of Lactobacillus plantarum (LAC) or its cell-free supernatant (CFS) did not cause adverse effects in Merino ewes. While both progestagens (FGA and MPA) induced vaginal discharge in 90.8% of ewes, LAC significantly reduced purulent/hemorrhagic discharge in the FGA group (29.7% vs. 47.6% in CFS; p < 0.05). FGA-based synchronization improved pregnancy rates compared to MPA (71.7% and 75.6% vs. 49.0% and 50.0%; p < 0.01). LAC did not significantly alter estrus timing or vaginal discharge scores in MPA-treated ewes.

Study Design

The study employed a 2 × 2 factorial design with 196 Merino ewes randomly assigned to four groups:
1. FGA + LAC
2. FGA + CFS
3. MPA + LAC
4. MPA + CFS.
Progestagen sponges (FGA or MPA) were inserted intravaginally for 14 days, with concurrent administration of LAC or CFS. Outcomes included vaginal discharge scores, sponge loss, estrus timing, and pregnancy rates.

Dosage & Administration

The study did not specify exact CFU counts for L. plantarum (LAC) or volume/concentration of CFS administered. Both treatments were delivered intravaginally via sponges impregnated with either live bacteria (LAC) or their supernatant (CFS).

Results & Efficacy

Vaginal discharge:
90.8% of ewes exhibited discharge at sponge removal.
LAC-treated groups showed lower purulent/hemorrhagic discharge in FGA sponges (29.7% vs. 47.6% in CFS; p < 0.05), but no significant difference in MPA groups (40.7% vs. 41.7%; p > 0.05).
Sponge loss:
FGA group had higher loss (13.2%) vs. MPA (5.7%; p = 0.07, trend toward significance).
Estrus timing:
FGA induced estrus earlier (36.8 ± 1.9 h) than MPA (49.1 ± 1.2 h; p < 0.01).
Probiotic treatment had no effect on timing.
Pregnancy rates:
FGA groups had significantly higher rates (71.7% LAC, 75.6% CFS) vs. MPA (49.0% LAC, 50.0% CFS; p < 0.01).

Limitations

Dosage ambiguity: LAC CFU and CFS concentrations were not quantified, limiting reproducibility.
Species-specific relevance: Results apply to ewes only; human applicability is speculative.
Trend-level significance: Sponge loss differences (FGA vs. MPA) approached but did not reach statistical significance (p = 0.07).
Short duration: Effects beyond 14 days were not assessed.
Confounding variables: Environmental or dietary factors in livestock settings may influence outcomes.

Clinical Relevance

For ovine reproductive management, L. plantarum (LAC) may reduce inflammation-related vaginal discharge in FGA-synchronized ewes, offering a potential non-antibiotic strategy to improve vaginal health. However, the lack of dosage details and human data means these findings cannot yet guide clinical use in humans. The superior pregnancy rates with FGA (vs. MPA) highlight its utility in livestock breeding programs. Probiotic treatments did not enhance fertility beyond progestagen type effects. Future research should explore dose optimization and mechanisms of discharge reduction in larger animal cohorts.

Source: PubMed (2025) | Sample: 196 Merino ewes | Type: Factorial randomized controlled trial