I have a 7 year old quarter horse mare whom is pregnant and due in the next 2 months. For the last couple of months she has had diarrhea. Her personality hasn't changed but I am just curious on what could possibly be wrong with her. Answers please??

Thank you

Oh goodness... There could be a lot of possibilities (none good) and there is no way for anyone here to determine the cause. This is a very serious situation especially since she's pregnant. Diarrhea can cause dehydration and malnutrition to her and the unborn. If care is not given to address the problem, you could lose them both during birth or perhaps sooner. Animals are masters at hiding what ills them. Her personality may not change until it's too late.
Please have a vet come out to your home to see your horse.