Abundance of Lactobacillus in Endometrium Affected by Chronic Endometritis

Inclusion Criteria: * Infertile (≥ 12 months of unprotected regular intercourse) premenopausal women or women with ≥ 2 consecutive miscarriages undergoing hysteroscopy. - Infertile women undergoing office hysteroscopy for other reasons, such as suspected intrauterine adhesions after curettage, irregular endometrium, uterine polyps, repeated implantation failure in assisted reproduction, etc. * Signed informed consent * BMI ≥ 18 kg/m2 and ≤ 40 kg/m2 * Age: ≥ 18 years and ≤ 45 years * follicle stimulating hormone (FSH) ≤ 20 (day 2-5 and estradiol ≤ 300 pmol/l) Exclusion Criteria: * Treatment with antibiotics in the past 3 months * Treatment with immune-suppressing or immune-modulating drugs in the past 3 months * Treatment with estrogens, progestins, contraceptives and/or antiestrogenic drugs in the cycle during which hysteroscopy is performed * Current infection of the cervix with Chlamydia trachomatis and/or gonorrhea * Pelvic surgery in the past 3 months * Suspicion of malignancy * Pregnancy * Breast feeding * Perimenopause (irregular menses and FSH ≥ 20 U/l on day 3-5 of the cycle) * Outdated endometrial sample from the luteal phase (this criterion will be evaluated during visit 4 post surgery) * Elevated progesterone concentration ≥ 20 nmol/l measured in the blood sample taken at the time of HSC. * Insufficient amount of tissue for immunohistochemical analysis and/or microbial 16s rRNA gene sequencing