Shih Tzu Breeding Guide: Heat Cycles, Pregnancy, Whelping, and Newborn Care
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How we researched this article: This guide is based on Cornell University’s College of Veterinary Medicine, VCA Animal Hospitals, the American Kennel Club, and the American Shih Tzu Club’s breeder guidelines. Every source is listed at the end. Last reviewed: September 2026.
Call your vet or an emergency clinic right away if a pregnant or new mother Shih Tzu: strains hard for 30 minutes without delivering a puppy, goes more than 2 hours between puppies, has green or dark discharge with no puppy born, bleeds heavily, or seems very weak. After birth, restlessness, panting, trembling, stiff legs, or seizures can mean a dangerous drop in calcium (eclampsia) and need emergency care.
This guide explains the Shih Tzu heat cycle, pregnancy, birth, and newborn puppy care. It is written for owners of female Shih Tzus that are not spayed, owners facing an unplanned pregnancy, and anyone thinking seriously about breeding.
Breeding is a big responsibility. It carries real health risks for the mother, takes weeks of round-the-clock work, and can cost far more than expected if a cesarean section or intensive care is needed. We strongly encourage working closely with a veterinarian at every step.
This guide replaces our earlier separate articles on the heat cycle, pregnancy, newborn puppies, and stud dogs.
The Shih Tzu Heat Cycle
According to Cornell University’s College of Veterinary Medicine:
- First heat: usually between 6 and 24 months of age. Small breeds like the Shih Tzu tend to start earlier.
- How often: most dogs come into heat about twice a year, every 5 to 11 months.
- How long: bloody discharge usually lasts about 14 to 21 days.
| Stage | Typical length | What you may notice |
|---|---|---|
| Proestrus | 6 to 11 days | Swollen vulva, bloody discharge. Males are interested, but she will not accept them yet. |
| Estrus | 5 to 9 days (can range from 1 to 20) | She may accept a male. Discharge often turns lighter or straw colored. This is the fertile window. |
| Diestrus | About 2 months | She no longer accepts males. Hormone levels stay high whether or not she is pregnant. |
| Anestrus | Several months | A resting phase while the uterus repairs. |
Caring for a Shih Tzu in heat
- Keep her on a leash outdoors and never leave her alone in the yard. Males can travel far and climb fences when a female is in heat.
- Keep her apart from intact males at home, even if they are related.
- Use washable dog diapers to protect furniture and bedding. Check and change them often to keep the skin clean.
- Expect mood changes, clinginess, or nesting.
Watch for pyometra after a heat. Pyometra is a life-threatening infection of the uterus that Cornell describes as common in unspayed females. Signs often appear a few weeks after a heat and include drinking and urinating more, low energy, loss of appetite, vomiting, a swollen belly, or discharge from the vulva. See a vet the same day. Spaying prevents pyometra.
- Paw Legend Washable Female Dog Diapers. Reusable diapers in small sizes for heat cycles. Measure your dog’s waist before ordering. Check price on Amazon →
Accidental Mating: What to Do
If your female mates by accident, call your vet as soon as possible. Your vet can explain the options, including monitoring for pregnancy or spaying. Some options only work within a short time after mating, so do not wait to see what happens. A tiny female bred by a larger male can face a much harder birth.
Should You Breed Your Shih Tzu?
Responsible breeding aims to improve the health and temperament of the breed. Before you decide, work through this checklist.
- Health testing. The American Shih Tzu Club’s breeder guidelines recommend eye exams every year, hip X-rays after 2 years of age, kidney screening, and other tests. Both parents should be tested before breeding.
- Age and maturity. VCA Animal Hospitals notes that the first heat is often not a good time to breed, and recommends waiting until at least the second or third heat. Many breeders wait until health testing is complete.
- Temperament and quality. The American Shih Tzu Club asks breeders to use only dogs of good quality without serious faults.
- Timing. Your vet can use progesterone blood tests to find the fertile window.
- Money and time. Plan for vet visits, an emergency cesarean section, puppy vaccines, and weeks of close care.
- Homes. Have screened, waiting homes before a litter is born. The American Shih Tzu Club recommends spay and neuter contracts or limited registration for pet puppies.
About stud dogs
Male Shih Tzus can produce sperm as young as 6 to 12 months, but that does not mean they are ready to breed. A stud dog should meet the same health testing standards as the female. The American Shih Tzu Club recommends a complete written stud contract.
If you do not plan to breed, spaying or neutering has health benefits and removes the stress of heat cycles. Our Shih Tzu spay and neuter guide explains the pros, cons, and timing.
Shih Tzu Pregnancy
VCA Animal Hospitals reports that pregnancy in dogs lasts 57 to 65 days, with an average of 63 days.
Confirming pregnancy
- Ultrasound: can detect pregnancy from about three weeks. Scans after day 28 are most reliable.
- Blood test: a relaxin test can confirm pregnancy, but may be negative if done too early.
- X-ray: around week seven is the most accurate way to count puppies. Knowing the number helps you know when birth is finished.
Feeding a pregnant Shih Tzu
- Keep her normal diet for the first six weeks.
- After week six, increase food gradually. VCA notes she may need up to 1.5 times her usual amount in the last three weeks.
- Offer smaller, more frequent meals as her belly grows.
- Ask your vet about switching to a puppy or growth formula food.
- Do not give calcium supplements unless your vet prescribes them. Extra calcium during pregnancy can raise the risk of eclampsia after birth.
How many puppies do Shih Tzus have?
Small breeds have small litters. A Norwegian study of 10,810 litters from 224 breeds found an average of 3.5 puppies per litter in the smallest breeds, compared with 5.4 across all breeds and 7.1 in giant breeds. Litter size also depended on the mother’s age and how she was bred. An X-ray around week seven is the best way to know how many puppies your Shih Tzu is carrying.
Preparing for Birth (Whelping)
- Set up a whelping box in a quiet, warm room at least a week before the due date, and let her get used to it.
- Line it with washable bedding.
- Keep your vet’s number and the nearest 24-hour emergency clinic’s address handy.
- Take her rectal temperature twice a day in the last week. Cornell reports that a drop below 99°F usually means labor will start within 24 hours. Normal temperature is 100 to 102.5°F.
What normal labor looks like
- Stage 1 lasts 6 to 36 hours. She may pant, shiver, pace, dig, or refuse food.
- Stages 2 and 3 are the birth of each puppy and its placenta. A puppy usually arrives within 30 minutes of strong contractions.
- Up to 2 hours between puppies can be normal. More than that is a reason to call your vet.
- After birth, a reddish-brown discharge can last 3 to 8 weeks. A foul smell or heavy discharge needs a vet check.
Have a plan for a cesarean section. Shih Tzus are small, flat-faced dogs, and some births need surgery. Talk with your vet ahead of time about what to do if labor stalls, especially after hours.
Caring for Newborn Shih Tzu Puppies
Warmth
The American Kennel Club explains that newborn puppies cannot control their own body temperature until about 2½ weeks of age. Keep the whelping area at about 85°F during the first weeks. Heat only part of the box, so the puppies can crawl away if they get too warm.
Nursing and weight
- Make sure every puppy nurses within the first hours after birth.
- Weigh each puppy at birth, at 12 hours, at 24 hours, and then daily. A kitchen scale that reads grams works well.
- The AKC notes that most healthy puppies roughly double their birth weight in the first week.
- Call your vet if a puppy loses weight or stops gaining.
Warning signs in newborns
The AKC lists these warning signs, especially in the first 72 hours:
- Not nursing, or being pushed away from the mother
- Lying on its side or with its mouth open
- Moving much less than its littermates
- Crying and restlessness even after nursing
Newborn puppies can decline very fast. Call your vet right away if you see any of these signs.
Watch the mother, too
- Check that she eats, drinks, and urinates normally.
- Check her mammary glands daily for heat, hardness, or redness, which can mean mastitis.
- Know the signs of eclampsia: restlessness, panting, trembling, stiffness, or seizures. This is an emergency.
Helpful supplies for new litters
- Etekcity Digital Kitchen Scale. Reads in grams and ounces, which makes daily puppy weigh-ins easy to track. Check price on Amazon →
- K&H Pet Bed Warmer. A low-wattage, thermostatically controlled pad that goes under bedding. Place it under only one side of the whelping box so puppies can move off the heat. Check price on Amazon →
Never use a human heating pad, which can get too hot and burn newborn puppies.
When Puppies Go Home
Puppies need their first vaccines and deworming, a vet check, and time to learn from their mother and littermates before going to new homes. See our Shih Tzu puppy vaccine schedule and Shih Tzu puppy care guide to share with new owners.
Frequently Asked Questions
How often does a Shih Tzu go into heat?
Most dogs come into heat about twice a year, every 5 to 11 months. The first heat usually happens between 6 and 24 months of age, and small breeds tend to start earlier.
How long is a Shih Tzu in heat?
Bloody discharge usually lasts about 14 to 21 days. The fertile period falls in the middle of the heat.
How long is a Shih Tzu pregnant?
Dogs are pregnant for about 57 to 65 days, with an average of 63 days.
How many puppies does a Shih Tzu have?
Shih Tzus usually have small litters. A large study found the smallest breeds averaged about 3.5 puppies per litter. An X-ray around week seven is the most accurate way to count the puppies.
When should I call the vet during birth?
Call if she strains hard for 30 minutes without a puppy, goes more than 2 hours between puppies, has dark or green discharge with no puppy, bleeds heavily, or seems weak.
Sources
- Cornell University College of Veterinary Medicine, Riney Canine Health Center. Dog Estrous Cycles.
- Cornell University College of Veterinary Medicine, Riney Canine Health Center. The Normal Whelping Process.
- VCA Animal Hospitals. Pregnancy in Dogs.
- VCA Animal Hospitals. Breeding for Pet Owners: Estrus and Mating in Dogs.
- American Kennel Club. Whelping and Caring for Newborn Puppies. 2025.
- American Shih Tzu Club. ASTC Breeder Guidelines.
- Borge KS, Tønnessen R, Nødtvedt A, Indrebø A. Litter size at birth in purebred dogs: a retrospective study of 224 breeds. Theriogenology, 2011.
This article is for general information. It is not a substitute for advice from your veterinarian. Read our medical disclaimer.
