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When your female dog is in heat and suddenly stops eating, it can raise understandable concern. Hormonal changes can affect her appetite, behavior, and overall comfort.
We outline the common reasons why a dog on her period may not be eating, what you can do at home, and when to seek veterinary help.
My Dog Is on Her Period and Not Eating — Why It Happens
When a dog is in heat (estrus), hormonal fluctuations can cause changes in appetite and mood. The release of estrogen, followed by progesterone, affects her physical and emotional state. These changes may lead to mild to moderate appetite loss.
Pain from cramping, stress from behavioral changes, or discomfort from the bleeding phase can also make her less interested in food.
However, this symptom should be monitored closely, as it may also signal other underlying issues.
Dog on Her Period and Not Eating: Common Causes
Hormonal Changes (Estrus Cycle)
During your dog’s heat cycle, hormonal changes affect her appetite.
Estrogen rises during the early phase of estrus, which often leads to a decrease in hunger.
Some dogs become picky eaters or avoid food altogether. You may also notice mood swings, clinginess, or withdrawal, which can affect her eating habits.
This is usually temporary and resolves after the cycle ends.
Pain or Cramping
Just like humans, some dogs experience abdominal discomfort during their period.
This discomfort may stem from uterine contractions or inflammation.
Dogs can’t verbalize this pain, but signs like restlessness, panting, and a tucked abdomen can indicate cramping. Loss of appetite can result from this discomfort.
Read more: Dog Nesting and Not Eating (Here’s when it’s serious)
Stress or Anxiety
Heat cycles are emotionally challenging for many dogs.
The hormonal rush can cause nervousness, irritability, and confusion, especially in unspayed females not used to these changes.
Behavioral shifts, such as hiding, whining, or pacing, can accompany appetite loss.
Environmental stress—like interactions with male dogs—can make it worse.
Infection (Pyometra)
If your female dog is intact and showing symptoms like not eating, vomiting, and discharge, this could signal pyometra.
Pyometra is a life-threatening infection of the uterus that occurs in unspayed females. It typically follows a heat cycle.
Dogs with pyometra may seem lethargic, refuse food, and often have a distended abdomen.
Pus-like discharge from the vulva and increased thirst and urination are red flags.
Gastrointestinal Upset
Sometimes, the loss of appetite is unrelated to the heat cycle.
Dogs may have eaten something they shouldn’t have or developed a GI issue (like gastritis or parasites).
If your dog is not eating and showing signs of nausea, vomiting, or diarrhea, these may be unrelated to her period and should be evaluated separately.
Pregnancy
A dog may lose her appetite in early pregnancy, particularly if mating occurred during her heat.
Morning sickness is real for dogs, too. If she was recently in contact with a male, and she’s not eating, pregnancy could be the reason.
Other early signs include nesting behavior, swollen nipples, and fatigue.
What to Do If Your Dog Is on Her Period and Not Eating
Make her environment calm and quiet. Reduce stimulation and noise, especially if she’s showing signs of stress. Offer her a comfortable, private space where she can rest.
Try tempting her with easy-to-digest, bland foods like plain boiled chicken and rice. Avoid rich or fatty treats, which may upset her stomach.
Keep her hydrated, even if she’s not eating. Offer fresh water frequently or use unflavored Pedialyte to maintain electrolyte balance. Broth-based ice cubes can also be enticing.
Maintain a routine, as disruption can worsen anxiety. Gentle walks and familiar patterns can help reduce stress.
Monitor closely. If she refuses food for more than 24–48 hours, or if other symptoms develop, consult your vet.
When to Call or Visit Your Vet
If your dog’s loss of appetite lasts longer than two days, it’s time to involve a vet. Extended fasting can weaken her immune system and mask serious issues.
Watch for signs of pyometra, such as:
Vomiting
Lethargy
Swollen belly
Pus or foul-smelling discharge
Excessive thirst or urination
If your dog has a fever, shivers, or seems to be in pain, urgent veterinary care is needed.
Refusal to eat combined with vomiting or diarrhea could mean a GI illness unrelated to her cycle.
If pregnancy is suspected, a vet can confirm and provide prenatal care guidance.
If you’re unsure whether her symptoms are normal for estrus or cause for alarm, always err on the side of caution.
Read more: Dog Not Eating and Acting Weird (What’s going on?)
Key Takeaway
It’s not uncommon for a female dog to eat less during her heat cycle. Hormonal changes, pain, and stress are the most frequent culprits.
But if her appetite doesn’t return or other symptoms arise, it could indicate something more serious, like pyometra or a digestive issue.
Always observe your dog closely and contact your vet when in doubt. With calm support and proper care, she’ll likely return to normal once her heat passes.