The goal of this clinical non-invasive observational pilot study is to improve the prediction of pregnancy success after In Vitro Fertilisation (IVF)/IVF -Intracytoplasmic Sperm Injection (ICSI) treatment by examining the vaginal microbiome and the immunological profile of menstrual blood in women (18-42) years old) undergoing their first IVF/IVF/ICSI treatment.

The main questions it aims to answer are:

What is the ReceptIVFity profile (low, medium, or high) of the vaginal microbiome in these women? How do the endometrial-derived lymphocytes respond to different immune stimuli and microbiota? Can the endometrial stromal cells decidualize effectively in the presence or absence of specific microbiota?

Participants will:

Self-perform a vaginal swab to determine the ReceptIVFity profile of their vaginal microbiome.

Self-collect menstrual blood during 24 hours in 2 blocks of 12 hours for immunological analysis.

Inclusion Criteria:

1. Indication for an IVF or IVF/ICSI procedure.
2. 18 years - 42 years.
3. European origin
4. Willing to provide a vaginal swab with the ReceptIVFity-test.
5. Willing to provide informed consent.

Exclusion Criteria:

1. No transferable embryos after IVF or IVF/ICSI.
2. Emergency IVF for cancer or other reasons.
3. Women with endometriosis pre-treated with an Gn-RH analogue.
4. The use of (hormonal) contraceptives or antibiotics 3 months prior to start IVF or IVF/ICSI.
5. Women unable or unwilling to agree with the procedures.
6. Women unable or unwilling to give written informed consent.

Women who receive IVF or IVF/ICSI treatment

Women aged 18-42 expected to undergo their first IVF/IVF-ICSI cycle within the next two months. The routine IVF/IVF-ICSI procedure will occur irrespective of their participation or the test outcomes.