5 year old dog discharge from nipple

Question
I have a female 5 year old mixed lab dog. She has not been spayed. She is overweight. I was giving her a bath a month ago and noticed a discharge from her nipples. Clear and a little brown but not what I would call bloody. It is not continous and only seems to occur around the time of her heat as I recall noticing it once before around the time of her going into heat. She is not bothered by it, has no other symptoms, and no lumps that I can feel. Could this be due to her overweight status or due to her not being spayed? As I stated this is not continual, the discharge is only if i apply pressure to the nipple, and only seems to occur around the time of her heat.

Thank you.

Answer
This discharge could be anything but since she is having it at the time of her heat I would say it might be from that, such as a hormonally induced false pregnancy lactation. Without looking at the dog and the discharge it would be hard to say what it is.

My question is why isn't she spayed at 5 yrs old? With her not being spayed and having these discharges, she is at an extremely high risk of getting mammary tumors, which is essentially breast cancer in dogs.

Get her on a diet and drop the weight off of her so she can be spayed. It is hard for an unspayed dog to get so heavy so her diet must be filled with human food and treats. Most people blame spaying for making their dogs obese, but as you can see, that isn't the case.

So if you want her to live a long and healthy life, instead of an uncomfortable and overweight one, do her a favor and get her on a good diet, stop feeding her any human food or dog treats and walk her.
Then you can get her spayed and lower her risk of cancers of the breast and of her uterus.

If the discharge becomes bloody, milky looking or changes she needs to see a vet.
I hope you can find a way to help her out. She depends on you for her care.