A single center，observational cohort study to explore the relationship between reproductive tract microbiota and pregnancy outcome in the patients accepted IVF/ICSI. To investigate whether there is a correlation between reproductive tract microbiota and IVF/ICSI outcomes. Whether there are differences in reproductive tract microbiota (such as vagina, follicular fluid, uterine cavity, etc.) in patients with different pregnancy outcomes.

A single center，observational cohort study will enroll 120 infertile participants and then divide them into 3 groups: 1)Male infertility；2)Recurrent implantation failure; 3)Recurrent spontaneous abortion. The study will last for 1 year and recruit participants in Reproductive medicine center of Peking university third hospital. Each participant will be followed up for at least 1 year. Collect samples and record information at the first month, then follow-up 2 months to record the pregnancy outcomes. DNA will be extracted from the samples and then have sequence to figure out the compositions of microbiota.

Inclusion Criteria:

1. The sampling cycle of all samples requires no use of glucocorticoids, antibiotics and vaginal drugs within the cycle of this month; No cervical treatment within a week; No irrigation, asexual life within 5 days; Strict contraception in this month;
2. Male infertility (Related tests were normal, because the male factor alone required the first IVF/ICSI cycle; Follow-up of included patients was conducted to determine whether embryo transplantation was performed, and the score of transferred embryos was recorded, and the final control group would be confirmed after achieving clinical pregnancy) OR Recurrent implantation failure (Previous ≥3 consecutive embryo transfer failures) OR Recurrent spontaneous abortion (≥2 consecutive spontaneous abortions or embryo damage)

Exclusion Criteria:

1. Acute genital tract inflammation (including vagina, cervix, endometrium and pelvic cavity)
2. Previous diagnosis of intrauterine adhesion or mechanical damage to the endometrium; drugs and surgery can not restore the function (endometrium thickness <7mm in the window period before transplantation)
3. Untreated hydrosalpinx, submucosal or >4cm intramuscular uterine fibroids, adenomyosis, stage III-IV endometriosis confirmed by surgery, endometritis diagnosed by pathology and other definite factors might affect implantation
4. Chromosomal abnormalities in couples may lead to miscarriage, fetal malformation and other diseases
5. Previous examination indicated the existence of DOR (FSH≥9U/L and/or AMH ≤1.1ng/ml and/or AFC≤5-7)
6. Those with polycystic ovary syndrome, high prolactinemia and other ovulation disorders
7. Those with congenital adrenal hyperplasia, hypothyroidism/hyperthyroidism, diabetes, metabolic syndrome and other endocrine and metabolic diseases
8. BMI less than 18 or more than 25
9. Previous autoimmune diseases such as anti-heart coagulation syndrome, sjogren's syndrome and rheumatoid arthritis
10. Prethrombotic hypercoagulability or family history of thrombosis
11. Female genital tract deformities (whether or not surgically corrected)
12. Those within the programme of oocyte or sperm donor
13. Those with previous history of various types of cancer or serious systemic diseases (such as heart, lung and blood diseases) or mental diseases

The recruited participants conformed to the eligibility criteria will be divided into 3 groups (Control group: male infertility; RIF group; RM group). Each group will be recruited at least 30 cases.