Many dog owners have questions regarding pregnancy in dogs: How long is a dog pregnant? How do they become pregnant? How can you tell they are pregnant?
If you are considering breeding from your dog, it is extremely important to educate yourself on the needs of your dog and her future puppies, breed standards and health test recommendations, and how to breed from your dog safely, all of which can be discussed with your veterinarian.
When can a dog get pregnant?
Female dogs usually hit puberty around 6-9 months of age, however, this can range anywhere between 5 and 24 months depending on size, breed, and individual dog. Once they reach sexual maturity, they begin to experience estrous cycles, also known as being “in heat” or “in season.” Estrus occurs approximately every 6 months for 1-2 weeks, but this can vary from dog to dog.
Female dogs can become pregnant as early as their first estrus (i.e., as puppies). While in estrus, they will allow unneutered male dogs to mate with them. This typically involves foreplay with playful behaviors and the male sniffing and licking the back end of the female, followed by mating, where the male mounts the female, eventually becoming “tied” (i.e., locked rear to rear). Female dogs can conceive even if they do not tie, so accidental matings that are separated before this stage can still result in pregnancy.
In general, it is recommended that female dogs do not become pregnant until their third estrus or until they are at least 2 years old since most are not physically or temperamentally mature before this. In addition, older female dogs have an increased risk of complications in pregnancy, so they should not be bred from.
How can you tell if your dog is in heat?
The canine estrous cycle consists of 4 stages: proestrus, estrus, metestrus, and anestrus. Proestrus occurs directly before estrus, and female dogs may become attractive to males at this time. Dogs in proestrus have bloody vaginal discharge and a swollen vulva, but they will reject any advances from male dogs.
Once they go into estrus (or “heat”), the discharge becomes thicker and less bloody with a pinkish-red tinge, and the vulva softens. At this point, the female dog will allow intact male dogs to mate with her, with ovulation typically occurring 1-3 days after estrus begins.
Female dogs may urinate more frequently during estrus, depositing pheromones to signal to local male dogs. They may also display changes in energy levels, appetite, or behavior.
Can a dog get pregnant when not in heat?
No—female dogs can only get pregnant when they are in heat, as this is the only time they will allow males to mate with them and the only time that they ovulate.
How long is a dog pregnant?
Canine pregnancy lasts for approximately 63 days, or 9 weeks. This may vary by a day or so on either side depending on when ovulation occurred.
During the first trimester (days 1-21), few changes may be seen besides a slight increase in body weight. A pregnant dog’s abdomen grows a bit bigger in the second trimester (days 21-42).
You may also see some enlargement of the mammary tissue, and some dogs may be more tired than usual with a reduced appetite. In the third trimester (days 42-63), the pregnant belly becomes much more apparent, as do the engorged mammary glands.
Due to hormonal changes, pregnant dogs may show some behavioral changes throughout the pregnancy such as being overly affectionate or irritable.
Shortly before birth, pregnant dogs will start nesting, and they should be given privacy, quiet, and suitable bedding materials. They may also start to leak milk, and their temperature drops sharply just before going into labor.
Stages of labor in dogs
Labor consists of 3 stages—early uterine contractions (stage 1), active straining and delivery (stage 2), and expulsion of the placenta (stage 3).
Normally, clear vaginal discharge is seen before a puppy is delivered in its amniotic sac. The mother will open the sac, bite the umbilical cord, and lick the puppy before allowing it to suckle.
Then, a dark green vaginal discharge is noted, followed by the placenta being expelled. Although each puppy has its own placenta, 2-3 puppies may be born before the mother expels their placentas.
It is important to be aware of the stages of labor and to be prepared mentally and financially for the possibility of a C-section should any issues arise during delivery.
You should seek immediate veterinary attention if your dog shows any of the following signs during labor:
- Unproductive straining for more than 30 minutes to 1 hour
- Part of a puppy protruding from the birth canal but not being delivered within 30 minutes
- More than 2 hours since the initial clear discharge appeared with no puppy delivered
- Foul-smelling discharge
- Stage 2 labor lasting more than 12 hours
Do pregnant dogs get morning sickness?
Like humans, dogs can experience nausea, vomiting, and reduced appetite in early- to mid-pregnancy due to hormonal changes. Luckily, these symptoms are usually short lived.
Dr. Diana Hasler graduated with distinction from the University of Edinburgh Royal (Dick) School of Veterinary Studies in 2018. She has experience working as a small animal veterinarian in general practice, where she has treated many dogs, cats, rabbits, and rodents.
How do I tell how far along my dog is?
Your dog’s mating history can help you determine a rough estimate of how far along your dog’s pregnancy is. Your veterinarian can also help with this. The best way to diagnose pregnancy in dogs is by abdominal ultrasound, which can be done from 4 weeks onwards.
It should be noted, however, that this method is inaccurate at predicting litter size. X-rays can detect fetal skeletons and litter size from 6 weeks onwards, but this is not usually necessary and has the potential to harm the fetuses due to radiation exposure.
There is also a blood test for pregnant dogs that can be performed from 4 weeks onwards that measures relaxin, a hormone produced by the placenta. Your vet may be able to palpate fetuses once your dog is a few weeks along, but this can be difficult in some dogs, such as overweight dogs, anxious/tense dogs, or those with a single pup.
Based on the date of mating, your dog’s heat cycle, and findings from physical examination and diagnostic tests, your vet can help you determine how far along your dog is in their pregnancy so that you can plan for the puppies’ arrival.