If you start noticing mysterious drops of blood following your female Shih Tzu puppy wherever she goes, you’re probably dealing with her first heat cycle. Coping with the moodiness and mess of a Shih Tzu in heat can be stressful, but it’s also unavoidable unless your dog is spayed. But how long will your Shih Tzu be in heat?
A full Shih Tzu heat cycle typically lasts 2–4 weeks, although the dog is technically only “in heat” for part of that time. In this article, we’ll answer some common questions about Shih Tzus in heat, including when you can expect their first cycle, the stages of the heat cycle, and when she is at risk of getting pregnant.
We’ll also give you some tips on managing your Shih Tzu while she’s in heat.
When Will My Shih Tzu First Go Into Heat?
Small dogs, like Shih Tzus, tend to have their first heat cycle earlier than large breeds. Female Shih Tzu puppies may experience their first heat as early as 4 months, but it can typically happen anytime between about 4–7 months.
Unless she is spayed or becomes pregnant, a Shih Tzu will generally go into heat twice a year, roughly every 6 months.

The 4 Stages of the Heat Cycle
- Proestrus
- Estrus
- Diestrus
- Anestrus
1. Proestrus
Proestrus, the first stage of the cycle, is when you’ll probably first notice signs of your Shih Tzu being in heat. A bloody discharge and a swollen vulva are the most common physical signs, along with increased peeing or urine marking. Your dog may also show behavioral changes like anxiety, moodiness, or being overly friendly toward male dogs.
During this phase, male dogs will be able to smell that your Shih Tzu is in heat, but she won’t be interested in their attention just yet. Proestrus usually lasts about 7–10 days.
2. Estrus
This phase of the heat cycle is when your Shih Tzu is technically “in heat.” The vulva stays swollen, but the discharge may become less bloody and pinkish. During this stage, your Shih Tzu will accept the attention of male dogs and can become pregnant.
Estrus may last 5–10 days on average, and you’ll need to be extra cautious about keeping your Shih Tzu away from any male dogs during this time if you want to avoid accidental breeding.

3. Diestrus
Diestrus occurs just after estrus and may last 10–14 days. During this phase, your Shih Tzu will either be pregnant or her reproductive system will be resting and getting back to normal. Her physical and behavioral signs of heat will fade.
4. Anestrus
Anestrus is the period between heat cycles lasting 4-6 months. Your Shih Tzu should be her normal self during this time.
How to Manage a Shih Tzu in Heat
While your Shih Tzu is in heat, she may be restless, anxious, and more vocal than usual. She will probably need to pee more than normal as well. Getting her out of the house for walks and exercise will help with both concerns.
Keep your dog on a leash and always have a sharp eye for any male dogs that may sniff her out. Unneutered male dogs can smell a female in heat from a long way off and do whatever they must to get to her. Never take your Shih Tzu to a dog park while she’s in heat.
If you have unneutered male dogs at home, keep them separated from your Shih Tzu while she’s in heat. That includes any males that might be related to her! To help manage the mess, you may want to consider confining your Shih Tzu to a room with an easily cleaned floor while she’s in heat. You could also have her wear a doggy diaper designed to contain heat discharge.

What If I Don’t Want to Deal with a Shih Tzu in Heat?
If all this sounds intimidating and stressful, you may prefer to avoid having a Shih Tzu in heat. Fortunately, all this can be prevented simply by having your dog spayed. Talk to your veterinarian about the best time to perform this procedure and ask any questions you may have about it.
Recent research has changed some long-term thinking on the risks of spaying some breeds at certain ages, so it’s worthwhile to discuss the pros and cons of the surgery with your veterinarian.
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Final Thoughts
Even if it seems like your Shih Tzu has been in heat forever, the cycle typically only lasts about 2–4 weeks. Your dog will need extra care and attention during her heat cycle and patience from you as she manages her hormone changes. Every dog experiences the heat cycle differently, but hopefully, this article provides a basic idea of what to expect when your Shih Tzu is in heat.
See also:
- How Fast Can Shih Tzus Run? Average Speed & Breed Comparison
- Will a Shih Tzu Be Good With My Kids? Everything You Want to Know!
Featured Image Credit: NcikName, Shutterstock