# Effect of Probiotic Supplementation on Reproductive Outcomes of Women With Polycystic Ovary Syndrome Who Are Candidates for Intrauterine Insemination: A Randomized, Double‐Blind, Placebo‐Controlled Trial

**Authors:** Tahereh Behroozilak, Mahsa Farshadfar, Samira Jahangard

PMC · DOI: 10.1002/edm2.70185 · Endocrinology, Diabetes & Metabolism · 2026-03-03

## TL;DR

This study found that probiotic use in women with PCOS undergoing IUI was linked to increased endometrial thickness, suggesting potential benefits for fertility.

## Contribution

The study is the first to show a potential link between probiotic supplementation and improved endometrial receptivity in PCOS patients undergoing IUI.

## Key findings

- Probiotic supplementation was associated with significantly higher endometrial thickness compared to placebo.
- The clinical pregnancy rate was higher in the probiotic group, though not statistically significant.
- Probiotic use had a positive effect on endometrial thickness in a regression model.

## Abstract

Evidence showed that microbial dysbiosis may lead to poor fertility outcomes. Today, therapy with probiotics, especially when using assisted reproductive technologies, is considered a potential method to improve outcomes. This study aimed to evaluate the effectiveness of probiotic consumption on reproductive outcomes in women with polycystic ovary syndrome (PCOS) who are candidates for Intrauterine Insemination (IUI).

In this randomized, double‐blind clinical trial, 100 women aged 19 to 37 years with PCOS who were candidates for IUI were studied in two groups (1:1): intervention and placebo. After ovulation induction and IUI, the study outcomes including chemical and clinical pregnancy rates, number of dominant follicles, and endometrial thickness were examined and compared in the two groups.

No difference was observed between the intervention and control groups in terms of basic demographic findings and paraclinical evaluation (p > 0.05). The chemical pregnancy rate in the intervention group was higher than in the placebo group, but no statistically significant difference was observed (16% vs. 12%; p = 0.564). The clinical pregnancy rate in the intervention group was higher than in the placebo group (14% vs. 4%; p = 0.081). The mean endometrial thickness in intervention groups was significantly higher than placebo group (p = 0.028), while the mean dominant follicle between the two groups was almost the same (p > 0.05). The regression model showed that only the probiotic supplementation had a significant positive effect on endometrial thickness in the intervention than the placebo groups (β = 0.618, 95% CI: 0.167–1.069, p = 0.008).

Probiotic supplementation for 8 weeks in women with PCOS who were candidates for IUI was associated with higher endometrial thickness, indicating a potential role in improving endometrial receptivity.

Probiotic supplementation for 8 weeks in women with PCOS who were candidates for IUI was associated with higher endometrial thickness, indicating a potential role in improving endometrial receptivity.

## Linked entities

- **Diseases:** Polycystic Ovary Syndrome (MONDO:0008487), PCOS (MONDO:0008487)

## Full-text entities

- **Genes:** PRL (prolactin) [NCBI Gene 5617] {aka GHA1, pPRL}
- **Diseases:** immune dysregulation (OMIM:614878), allergies (MESH:D004342), thyroid disorders (MESH:D013959), ET (MESH:D014591), anovulatory infertility (MESH:D007246), endocrinopathy (MESH:C567425), cardiovascular diseases (MESH:D002318), PCOS (MESH:D011085), Cushing's syndrome (MESH:D003480), hyperprolactinemia (MESH:D006966), autoimmune disease (MESH:D001327), Dysbiosis (MESH:D064806), diabetes (MESH:D003920), lung, pancreas, kidney, liver, (MESH:D010190), metabolic disturbances (MESH:D024821), IUI (MESH:D005317), inflammation (MESH:D007249)
- **Chemicals:** folic acid (MESH:D005492), lipid (MESH:D008055), starch (MESH:D013213), Lactofem (-), maltodextrin (MESH:C008315)
- **Species:** Bifidobacterium breve (species) [taxon 1685], gut metagenome (species) [taxon 749906], Streptococcus thermophilus (species) [taxon 1308], Homo sapiens (human, species) [taxon 9606], Lactobacillus acidophilus (species) [taxon 1579], Lactobacillus delbrueckii subsp. bulgaricus (subspecies) [taxon 1585], Bifidobacterium longum (species) [taxon 216816]
- **Mutations:** C-8 C

## Full text

_Full body text omitted from this summary view._ Fetch the complete paper as Markdown: https://tomesphere.com/paper/PMC12956837/full.md

## Figures

1 figure with captions in the complete paper: https://tomesphere.com/paper/PMC12956837/full.md

## References

41 references — full list in the complete paper: https://tomesphere.com/paper/PMC12956837/full.md

---
Source: https://tomesphere.com/paper/PMC12956837