Dog with clear brown fluid expressed from nipples

[Chelb2015]

My female dog is in heat. She has never had a liter or sex for that matter. I was inspecting her teats and they are bigger but not swollen, red or have any bumps whatsoever. She does however have clear brown fluid come out when I squeeze her nipples. I've tried looking online but they all say mastitis or cancer but other than the fluid, her teats are normal. Now I am worried sick. Can someone explain or help please.

[specialmom]

Unfortunately you probably need to have her seen by her vet. She could have an infection.  It also could be some kind of blockage in the breast duct.  They also talk about cysts that can cause this.  Here is an older post about it. https://www.medhelp.org/posts/Animal-Health---General/Brown-discharge-from-dogs-nipple/show/994023  I would get her checked out. Absolutely does NOT have to be cancer.  You want to rule that out but there are other harmless things it could be.