Abundance of Lactobacillus in Endometrium Affected by Chronic Endometritis

Difference in Relative Abundance of Lactobacillus in Endometrium With and Without Histologically Proven Chronic Endometritis

Infertile women undergoing hysteroscopy for diagnostic or therapeutic indication are asked to donate a sample of endometrium.

Endometrial samples of study participants are examined for signs of chronic endometritis by immunohistochemical analysis.

High-throughput sequencing of the microbial 16s ribosomal ribonucleic acid (rRNA) subunit is performed to identify and quantify the microbes present in the sample.

Obstetric and reproductive outcome is recorded 12 months after hysteroscopy (telephone interview).

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• Outdated endometrial sample from the luteal phase (this criterion will be evaluated during visit 4 post surgery)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