The reproductive tract microecology is an important part of the human microbial system. Microorganisms and the host reproductive tract environment form a stable symbiotic relationship. When pathogens invade or microecology imbalance，it can lead to serious reproductive tract infection.Reproductive tract infection is one of the most common disease among women，and it is a global social and public health problem. Reproductive tract infection is characterized by high morbidity, low cure rate and high recurrence rate.Data from the studies shows that 40% of Chinese women suffer from reproductive tract infections of varying degrees, that is, at least 200 million. Long-term chronic infections can lead to serious consequences such as infertility, tumor, abortion and premature birth. At present, the diagnostic classification of reproductive tract infection is mainly divided into Aerobic vaginitis（AV), Bacterial vaginosis（BV), Vulvovaginal candidiasis（VVC) and Trichomonas vaginitis（TV). The reproductive tract microbiota is complex, but the clinical classification is relatively simple, which makes the treatment lack of precision. More precise treatment，permanent cure and reducing the recurrence rate are the top priorities in the field of medical and health.

At present, the treatment of vaginitis is dominated by anti-pathogen medicine. While killing pathogenic microorganisms, it also inhibits the growth of normal vaginal lactobacillus, which further aggravates the vaginal microecological imbalance and makes it the root of refractory, drug-resistant and recurrent reproductive tract infections.

A growing number of studies show that the key point of the treatment for reproductive tract infections is to adjust the proportion of vaginal microorganism composition, in order to achieve the initial Lactobacillus dominant state, and maintaining the balance of vaginal microecology .

The composition and proportion of microorganisms in the lower reproductive tract influenced by a variety of factors, such as changes in sex hormone levels and phases of the menstrual cycle, sexual activity, antibiotic treatment and use of oral contraceptives, vaginal irrigation, menopause, pregnancy, breastfeeding, diabetes and stress . Also, there are obvious differences between different ethnicities and regions . Therefore, we need to conduct correlation analysis on the microbiota structure and various indicators of the Chinese population, and develop a more reasonable method for classifying lower reproductive tract infections and treatments. According to this classification method, accurate diagnosis of vaginal disease is further carried out, more rational treatment options can be implemented，and the health of patients is effectively improved.

Based on the above background, the study collected DNA from vaginal secretions from about 10,000 healthy Chinese women of reproductive age. And the DNA was tested by next genetic sequencing.The data obtained in this project will establish the baseline of the lower reproductive tract microbiome of Chinese population, and will be used for future research and comparison. The results will be used to explore the comparison of the lower reproductive tract flora of the population in different regions of China, and of the Chinese population with other ethnicities worldwide.

Inclusion Criteria:

• Women of childbearing age who are physically and mentally healthy, have regular menstruation and are between 20-45 years old;
• Women who are evaluated as normal by vaginal microbiome morphological characterization;
• Women who agree to participate in this study and have signed an informed consent form;
• Those who have full capacity for civil and legal conduct;
• The quality of vaginal samples meets the evaluation requirements of this program.

Exclusion Criteria:

• The sampling quality of vaginal secretions does not meet the research study requirements;
• The quality or format of the slide collection of vaginal smears does not meet the requirements;
• Women with severe physical or mental illness;
• Users of hormone therapy and antibiotic drugs;
• Women with insufficient compliance with this study;
• Women who are participating in other coinciding clinical drug or medical device trials.

Women of childbearing age who are physically and mentally healthy, have regular menstruation and are between 20-45 years old;

The comparison of the lower reproductive tract flora of the population in different regions of China, and of the Chinese population with other ethnicities worldwide.