What is the endometrium?
The endometrium is the mucous layer of the uterus where the fertilized egg attaches. The endometrium, or uterine lining, located in the innermost part of the uterine wall, is thus a key factor for successful conception. The uterine lining is commonly assessed using ultrasound, which evaluates only its height and structure. However, its bacterial flora (microbiome) and the so-called “implantation window”, the appropriate time for transferring the embryo to the uterus, are also crucial.
Due to hormonal imbalance in a woman’s body (dominance of estrogen over progesterone), it can happen that the uterine lining grows outside the uterus. In such a case, it is a disease called endometriosis.
Bacteria in the uterus prevent the successful implantation of the embryo.
The balance of bacteria in the endometrium is important for the successful implantation of the embryo. If pathogenic bacteria are present in the uterus, this balance can be disrupted. A test named ALICE (Analysis of Infectious Chronic Endometritis) can detect the presence of these bacteria causing chronic inflammations. These inflammations, found in up to 30% of infertile patients, may also be one of the causes of recurrent miscarriages. However, with appropriately chosen treatment, this situation can be resolved.
By taking a sample of the uterine lining and analyzing it using next-generation sequencing (NGS), other bacteria causing female infertility can be detected. The EMMA (Endometrial Microbiome Metagenomic Analysis) test can provide a complete overview of the composition of the uterine lining. In case of a non-optimal bacterial representation, it will recommend appropriate treatment with antibiotics or probiotics. The EMMA test also includes the ALICE test.
Is it the right time for embryo transfer?
Repeated unsuccessful embryo transfers can be demanding for a woman, both physically and emotionally. Even though the treated couple has undergone a series of tests and their embryos are ready for transfer to the uterus according to the results of preimplantation genetic testing, the uterine lining might not be prepared for this transfer.
The implantation window, the exact time when the uterine lining is ready for the embryo to implant, can be determined by the ERA (Endometrial Receptivity Analysis) test. Its results also help to determine the appropriate hormonal preparation and its duration. With the use of this test, a 73% implantation success rate (Implantation Rate) is achieved in patients with repeated implantation failure.