What is the Origin of Progesterone-Induced Blocking Factor?

The term originated in reproductive immunology and endocrinology research that sought to explain the paradoxical and vital phenomenon of the fetus, which carries paternal antigens, not being rejected by the mother's immune system. Its discovery highlighted a novel, non-genomic pathway by which progesterone exerts its effects, separate from its traditional role as a nuclear transcription factor. The concept is central to understanding the mechanisms of successful pregnancy and the pathology of recurrent miscarriage.

What is the Mechanism of Progesterone-Induced Blocking Factor?

Progesterone stimulates the efficient production of PIBF, which then acts directly on natural killer cells and T lymphocytes to suppress the production of pro-inflammatory cytokines like interferon-gamma. By promoting the protective Th2 cytokine profile, PIBF helps create an immune environment that is highly conducive to fetal survival and implantation. Furthermore, PIBF has been shown to regulate the synthesis of specific progesterone receptor isoforms, intricately linking the hormonal and immunological control of pregnancy.

Progesterone-Induced Blocking Factor

Meaning

Progesterone-Induced Blocking Factor (PIBF) is a specialized protein secreted by immune cells, particularly lymphocytes, in direct response to progesterone signaling. This critical factor plays a crucial immunomodulatory role by shifting the maternal immune response from a pro-inflammatory Th1-type to a protective, anti-inflammatory Th2-type. PIBF is absolutely essential for maintaining immune tolerance at the maternal-fetal interface, thereby actively protecting the developing embryo from immunological rejection during pregnancy.

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What Are the Most Important Lifestyle Factors to Maintain during Pregnancy after IVF?

Maintaining metabolic health, hormonal stability, and emotional equilibrium creates the optimal biological environment for a post-IVF pregnancy to flourish.

∞ Fatty Acids
∞ Blood Sugar
∞ Progesterone-Induced Blocking Factor