Should my 4 week pregnant dog have pale yellow discharge from its vagina?
It sounds to like an infection. I have been told a discharge the color of pale yellow, or mustard is really bad. It is a sign of pyo. And, the female will not make it if she is not gotten to the vet within hours of first noticing the discharge. The uterus is infected and it will kill her. You need to get her to the vet NOW!!! Do not take a chance. Anything yellow and mustard color looking is deadly. Sorry. It will require an emergency spay, but your female will still be alive, assuming you get her there in time.