Polycystic Ovary Syndrome is kind of disease with unclear etiology. Recent studies on intestinal microbiota have raised the possibility that dysbiosis of intestinal microbiota maybe a novel theory for the development of Polycystic Ovary Syndrome. Hence, the investigators will compare the intestinal microbiota composition and diversity in PCOS with age, BMI-matched control and then assess whether intestinal microbiota modification is associated with clinical and biological parameters.

The goal of this study is to investigate and compare the composition of the intestinal microbiota in patients with PCOS and age, BMI-matched control. In addition, the investigators will investigate the relationship between alterations in the intestinal microbiota, clinical phenotype, biochemical analysis, body composition, inflammation and food consumption habit. The investigators hypothesize that alterations in the intestinal microbiota are associated with increased immune activation and progression of PCOS. Based on this hypothesis, the investigators propose the following aims:

Aim 1. Identify and enroll cohort with PCOS and age, BMI-matched control to study the role of intestinal microbiota on the development of PCOS.

1. Enroll participants at Drum Tower Hospital. Identify and classify participants through initial clinical evaluation, collect clinical metadata, obtain and process blood and stool samples for analysis.
2. Characterize the intestinal microbiota through quantitative PCR and high throughput sequencing analysis of stool specimens in participants.

Aim 2. Compare sequencing results and metagenomic analysis for study groups with particular attention to bacterial composition and metabolic capacity associated with energy harvest, lipid and carbohydrate transport, enhancement of epithelial barrier integrity and systemic inflammation.

Inclusion Criteria:

1. Premenopausal between 18-40 years of age.
2. Exclusion of other etiologies for infertility.

Exclusion Criteria:

1. During the pregnancy and lactation period.
2. Use of antibiotics within 3 months.
3. Regular use of proton pump inhibitors, laxatives or pro-prebiotics.
4. Previous history of gastrointestinal surgery or disease (such as peptic ulcer, irritable bowel syndrome, inflammatory bowel disease or other gastrointestinal disorder).
5. Major changes in eating habits within the past 3 months.

Polycystic Ovary Syndrome patients and age, BMI-matched women.