Immune tolerance of pregnancy, also known as maternal immune tolerance, is the immune tolerance shown towards the fetus and placenta during pregnancy.
This essential biological process counters the typical immune response that would otherwise treat the fetus and placenta as foreign bodies. Normally, the immune system works to identify and eliminate anything recognized as non-self. However, during pregnancy, specific mechanisms are activated to prevent this rejection, allowing the pregnancy to proceed successfully.
Why is Maternal Immune Tolerance Necessary?
The fetus inherits genetic material from both parents, making it semi-allogeneic (partially foreign) to the mother's immune system. Without the development of immune tolerance, the mother's body would likely mount an immune attack against the fetus and placenta, similar to how it would reject a transplanted organ.
This tolerance ensures:
- The fetus is not recognized and attacked as a foreign invader.
- The placenta, vital for fetal development and nutrient exchange, is accepted.
Consequences of Impaired Immune Tolerance
When immune tolerance towards the fetus and placenta is not properly established or maintained, it can have significant consequences for the pregnancy. The reference explicitly mentions one such outcome:
- Spontaneous abortion: This can happen when the mother's immune system fails to tolerate the pregnancy and mounts a rejection response.
In essence, immune tolerance of pregnancy is a finely tuned balance that allows the mother's immune system to protect her from pathogens while simultaneously nurturing and accepting the developing fetus.
