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Biological Stimulation of Endometrial Receptivity (BISER) utilizes biological therapies to improve the quality of the endometrium and increase the chances of successful implantation. Biological therapies, based on cells and their products, utilize various cells such as platelets/leukocytes in enriched plasma (PRP, PLRP), fibrin enriched with platelets (P-BRF), or leukocytes (L-BRF), aiming to enhance endometrial receptivity.

Indications for BISER include:
• Repeated failure of embryo implantation in IVF procedures.
• Thin endometrium at the time of embryo transfer.
• Dysfunctional implantation – spontaneous abortions, missed abortions.

The use of hcPRP (platelet-rich plasma) to improve endometrial receptivity is increasingly focused on assisted reproduction techniques. Studies have shown that intrauterine application of autologous PRP increases pregnancy rates and live births, especially in patients with thin endometrium.

The procedure involves several phases:
1. Blood collection from a vein.
2. Preparation of hcP(L)RP and BRF in a closed automated system.
3. Preparation of thrombin activator.
4. Ultrasonography-guided intrauterine application of the prepared activated BRF, hcPRP,

  • Transcervical application of the activated substrate into the uterine cavity.

  • Transmyometrial sub-endometrial injections.​

Levels - there are two levels of BISER therapy:
1. Basic involves the application of autologously activated hcPRP and hCG.
2. Advanced involves the application of autologously activated BRF (in sub endometrial
applications), hcPRP, and hCG.

The procedure is performed in the same cycle as the embryo transfer (ET), 2-7 days before the actual ET, often around the time of cell aspiration. The entire process is performed under analgo-anesthesia and does not require hospitalization.

This method enriches the endometrium naturally - with autologous factors that influence endometrial receptivity. Peripheral blood components, such as platelets, have a proven role in remodelling the endometrium and positively coordinating between embryos and the endometrium. This facilitates implantation and improves endometrial vascularity.

Embryo transfer optimization (with additional analysis) is the procedure performed in the cycle preceding embryo transfer. These analyses pertain to the presence and quantity of NK cells, and plasma cells, as well as an analysis of the endometrial microbiota. These analyses are commonly conducted concurrently with endometrial scratching, around the potential implantation window. Depending on the findings, antibiotics, probiotics, or immunotherapy may be introduced as part of the preparation for embryo transfer.

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