Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 16 years of experience. I look forward to working with you.
I am sorry you are experiencing this with Lyla. Usually we do not see bloody stool. You would still see discharge from the vulva if this was related to being in heat still. So, it is important to try to determine if this looks to be a bloody stool problem or that she may still be experiencing an atypical estrus period of time. It should not come from cleaning herself (if she licks it, the blood would be digested and not come out red).
If you are certain the bloody discharge is from her vulva and not primarily stool, then unfortunately I must say it can be normal for bloody vulval discharge to occur for up to 7 weeks in some dogs who have an extended proestrus/estrus. Sometimes the first heat cycle is very irregular. This will usually resolve once she ovulates (discharge will disappear and body will normalize). You need to work with your veterinarian to ensure she does not have vaginitis or pyometra (uterine infection). Your vet can do vaginal cytology to look for which stage of estrus she may be in; this can tell us if she is actually out of estrus or not (swelling and discharge doesn't really tell us this unfortunately). And progesterone levels can also be helpful to know if and when she might ovulate (and then all the discharge disappear). If you were planning to have her spayed after her first heat cycle then it is incredibly important that she be well beyond ovulation as can be confirmed with progesterone levels; otherwise if she is spayed prior to that it could create a profound false pregnancy situation that could last weeks to months. I wish there was an easy hormone injection your vet could give to make her "stop" but there is not. :(
As a side note I must ensure she has no exposure or contact with human skin to which HRT (hormonal) cream, spray or gel has been applied. This can cause these symptoms unrelated to a dog being in heat.
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