The investigators aim to examine the endometrium with state of the art sequencing techniques to investigate the endometrial microbiota. The endometrial microbiota has been perceived to be sterile, however, this seems incorrect from recent studies. Thus, the primary outcome is to compare the rate of ascending infection from the semen to the vagina to the endometrium and to investigate which bacteria are capable of inhabiting these environments. Furthermore, cervical mucus will be obtained in order to test for immunological, microbiological and mechanical properties that may be involved in ascending infection. Finally, the study aim to characterize the temporal changes in the vaginal microbiota during estrogenic treatment with Estrofem® or Vivelle Dot (R) for preparation of the endometrium prior to embryo transfer.

Inclusion Criteria:

• Patients in IVF Freeze-all/segmentation treatment protocol.
• Written informed consent.

Exclusion Criteria:

• Uterine malformations
• HIV, Hepatitis B or C positivity. HPV CIN 2 or higher. Chlamydia trachomatis positivity.
• Any uncontrolled concomitant disease (e.g. uncontrolled diabetes, uncontrolled hypertension etc.)

Infertile couples attending IVF treatment and referred to a segmentation protocol.

Part of PhD project. Data will appear in the thesis and subsequent publications.