I'm really sorry Sanibo but as far as i am aware, there aren't any natural remedies for autoimmune issues.
There are natural remedies to treat the physical symptoms that can happen but nothing that would prevent the body from attacking something like an embryo.
To achieve a reduced immune response you would technically need to poison your system and weaken your bodies ability to fight which requires specific medication or else it can not only be dangerous to you but to any pregnancy too.
The doctor talked to me about steriods, which i know sounds scary but needs must... I believe aspirin can also have an impact but i dobt it would be significant enough.