Hot Issue – Pregnancy in Dogs and Cats

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Facts and Myths about pet pregnancy
Breeding and Pregnancy in Dogs and Bitches
Danger signs in dogs to watch out for during and after the birth
Breeding in Cats – Toms and Queens
Danger signs for Cats
Unwanted Pregnancies

Most pet owners only realize that their pets are pregnant when their pets are more than half way through their pregnancies. Whether your pet’s pregnancy was intentional or not (on your part), you have some choices ahead of you. This Hot Issue will hopefully equip you to deal with what lies ahead.  I hope to give you the facts and dispose of the old wives tales about canine and feline pregnancy in this article.

Seven week pregnancy in bitch

Note the enlarged belly and nipples in this 7 week pregnant bitch


Your cat or dog will happily mate with his/her own brother, sister, mother or father.

Your dog or cat can, in rare cases, be able to mate and breed from four months of age.  Cats can do this when the daylight length increases, as cats mate in spring and summer, so even kittens of four months of age can be mated.

Other animals will be able to gain access to your property and mate with your pet, even if you have four foot walls all round your yard.

Your pet may become an escape artist and run away, which they have never done before, in search of a mate. This also holds for males who smell or hear a female in season. This puts them in danger of getting run down by cars, getting into fights over potential mates and cats can pick up the fatal viruses causing feline AIDS or Leukemia at this time.

Animals separated by a four foot or less fence will easily clear it to get to each other. It’s best to confine males and females in season in entirely different places.If they are separated by a gate in a wall and you have staff or small children going in and out through the gate, the odds are that at some point, the dogs will get to each other.


a four foot fence will not stop a dog in season

Four foot fences will not stop medium to large dogs from clearing them

Purebred animals will not stick to their own breed and will mate with whatever catches their eye.

Big dogs can mate with miniature dogs, both ways. Don’t think that because you own a Rottweiler, your terrier won’t be able to do anything.

Dogs can fertilize bitches even if there is no coital tie.

A litter of puppies or kittens can easily have a number of different fathers.

Both cats and dogs mate more than once when they are fertile and the more they mate, the higher the chances of pregnancy and larger litter size.

A bitch won’t necessarily stand for every single male. They appear to have preferences in their choice of mates.

It is not advisable to allow a six month old bitch or queen to have a litter as they are still growing themselves. Rather wait until they are at least two years old before breeding with them.


Do not breed with 6 month old animals

Do not allow a 6 month old kitten or pup to breed – they are still growing



Bitches are fertile for the first time anytime from four months (rare) to over a year. Small breeds mature faster and are most likely to have their first season at around seven months of age. Giant breeds may be over a year of age before they have their first season. Male dogs are fertile from approximately eight months of age. Remember these figures are approximate only – each animal differs, so if you have a six month old pup, do not assume he is infertile because he is not eight months old yet.  Fertility in males and females starts to decline as they get older and it is rare for animals over eight years of age to successfully mate and produce litters without problems.

When to breed giant dogs

Giant breeds can only start cycling over a year of age and should not be bred before two to three years of age

Bitches are in heat approximately every six months (giant breeds may have longer intervals) and the heat lasts plus minus three weeks. If you are separating animals, you should keep them apart for the entire period. The bitch is not fertile for the entire heat. Most bitches start being fertile around day 11 of their heat. (Day one is when the bleeding starts) They remain fertile for around or just under a week, and then their fertility declines.

Day 1 -10: The vulva starts to swells and drops of blood fall out at intervals. Some bitches bleed copiously and some hardly at all. At this point the bitch is very attractive to males but most won’t allow the male to mate with them. The body is producing estrogen at this time.

Hormones of dogs in pregnancy

Blood tests for progesterone levels can predict the best time for mating

Day 11-18(16-20): The bleeding may decrease slightly during this fertile period but not always. The bitch will allow the male to mate with her – she will stand for the male. To test if she is ready, tickle her perineum (area between the anus and vulva). If her tail moves to the side and vulva lifts up, she is probably ready to stand for the male. If mating occurs, the female’s vagina clamps down on the penis of the dog inside and the two dogs are literally “tied” together.  At this point the male dismounts and tries to get off but is stuck and so he will turn to face the opposite direction from the female until mating has finished. This is known as a coital tie. This is perfectly normal so don’t panic. The bitch ovulates during this time, estrogen stops being produced and progesterone starts to rise. This is why many breeders measure the progesterone level in the blood to see when a bitch is ready for mating so they can time it exactly.  Your veterinarian can also do a vaginal smear to check for certain types of vaginal cells at this time to see if your bitch is ready for mating. The progesterone levels are the most accurate way of knowing, followed by the vaginal smear, then the behavior of the bitch.

Dogs get stuck together during mating

Dogs stuck together in a “coital tie” during mating

Day 19-21: The bleeding slows down to be replaced by a whitish pussy looking discharge. She is no longer fertile and her heat is ending.

Day 21+:The vulva will shrink slowly back down to normal size but the nipples may enlarge for up to two months afterward, regardless of whether she is pregnant or not. If she is an older bitch, she runs the rick of picking up uterine infections (pyometra) at this time. See our article on sterilization for information on this deadly disease

Pregnancy tests for dogs are available in some countries

Pregnancy blood tests for dogs are available in some countries

Bitches are pregnant for approximately 65  days but this number can vary from 58-72 days in extreme cases.

Puppies can be identified easily by physical examination and ultrasound at 4 weeks (although they can be picked up earlier depending on the skill of the vet or ultrasonographer and also on the litter size, and the shape and size of the bitch) and by X ray after 56-58 days. Some countries also offer a blood pregnancy test for the hormone relaxin.

Puppies on an x ray late pregnancy

See the heads and fishbone- like appearance of pups on a X ray

The nipples start to fill with milk approximately 7 days before she is due but is not always the case.

The temperature of the bitch will drop about 1 degree 12-24 hours before she is due to give birth and return to normal on the day of the birth.

Bitches should not receive live vaccinations during pregnancy, but they should be wormed and put onto puppy food during the pregnancy as puppy food contains more protein and calcium than adult food.

You should prepare a large basket or crate with  a soft cushion in it and pieces of blanket cut up small for warmth. (pups can get trapped under a whole blanket.) Give this to her to sleep in and put her food and water there about two weeks before she is due as during this time she may be looking for a nest and you may see her digging holes etc. in the garden to have her pups in.  Don’t allow other dogs, especially males to share this place with her and they should be kept away from the spot at all times. Be prepared to throw the cushion away after as the placenta has a green-black pigment that stains bedding.


A greenish black discharge BEFORE anything has happened is an emergency. It means the placentas are detaching but birth is not proceeding normally and the pups will suffocate inside unless drastic action is taken. This CANNOT WAIT till morning before seeing the vet.

A pup that has been born but is being ignored by the mother inside the sac needs to be taken out by hand and rubbed with a warm towel until it breathes otherwise it will die. Rub for at least 5 minutes before deciding the pup is not going to breathe. You can tie the umbilical cord in 2 places with boiled cotton and cut it between the knots.

A puppy that appears to be stuck halfway out the birth canal – call the vet.

Puppy in birth canal when to interfere?

A pup halfway out and still inside the sac.

Unproductive heavy straining for more than twenty minutes – call the vet

Heavy bleeding out the vulva. – call the vet

Straining for more than sixty minutes on and off with no results – call the vet

When the pups are three weeks of age, small breed dogs with large litters can develop “Milk Fever” – which is a fever and continuous shivering due to a lack of calcium in the blood. The pups need to be removed, bottle fed and the bitch needs to be hospitalized on a drip with calcium overnight.  Owners should continue to bottle feed the pups until weaning or it will happen again. Puppies can be weaned at four weeks but should still have milk as well until at least 6 weeks. They can have this mixed with the food or by bottle.


Cats breed during the summer months as a norm, but cats that are kept indoors in artificial lighting and heat do sometimes come into season in winter.  Females can come into season every three weeks from the time summer starts and the heat ends either when they have been mated or after about three days. They cycle until the daylight length starts to increase, so the odds of your cat getting pregnant are pretty high! Cats in season do not bleed like dogs do, but rather “call” to males. This is a very distressing sound for owners and they often think the cat is in pain. Cats also stick their hindquarters up in the air a lot more, so owners are often convinced there is something wrong with their legs or back. They may also be a lot more affectionate and roll over a lot more. The vulva is usually slightly more swollen than normal.


Normal cat uterus

The normal cat uterus. Note the 2 horns and the ovaries on the end of each horn

Most owners hear rather than see their cats mating as cat mating can be rather more brutal than dog mating. The males have barbs on their penis and they also bite the female as they are mating with her, which makes her give out a cry, turn round and often smack the male back. She will then clean herself.  More than one male may be present at a mating, and once she has recovered from the pain, will readily allow a second mating with the same or a different male.  If the mating does not lead to a pregnancy, she will cycle again in a short time.

Cats are pregnant for approximately 56 days.

They usually do not have as many difficulties as dogs do. If cats are stressed while birthing they can delay the birth until they feel that it is safer to give birth.

You should prepare somewhere safe for your cat to give birth when she is about a month pregnant and get her used to the spot, putting her food and water and litter nearby for her comfort. The spot should be away from dogs and very small children who can threaten or distract her. It should be somewhere closed. Cats on their own often choose to have their kittens under the bed or in the cupboard, which are areas that feel safe to them.


Uterus cat early pregnancy

In early pregnancy, the uterus looks like a string of pearls. This was taken from a feral cat


If she is ignoring a kitten inside a sac that has already been born, you need to open the sac and rub the kitten with a warm towel until it breathes. Rub for at least 5 minutes before deciding the kitten is not going to breathe.  You can tie the umbilical cord in 2 places with boiled cotton and cut it between the knots.

If there is a lot of heavy bleeding call the vet.

If there is heavy straining for more than twenty minutes call the vet.

If there is a kitten stuck in the birth canal call the vet.

For hand rearing abandoned kittens see our article on handrearing kittens


If the pregnancy is unplanned, many owners are left feeling guilty and uncertain about what to do next.

Option 1: If you allow your bitch or queen to have her litter, you MUST have her sterilized as soon as possible! Cats fall pregnant again while the kittens are still with them and a few weeks old. Cats can be sterilized when their kittens are weaned and between 4-8 weeks of age. Dogs can be sterilized once the puppies have been homed and the teats have gone down.

Option 2: Sterilization. If the pregnancy is already established you can choose to terminate and sterilize your pet at the same time. This is a difficult choice for many owners as it involves aborting puppies or kittens. The responsible thing is to have them sterilized before they can breed for the first time. This is usually the choice of people who work with pet rescue shelters, feral cats, or multi cat households where population control is desperately needed


Sterilizing an unwanted pregnancy in a cat

Sterilization of cat 4-5 weeks into pregnancy. Cat was from a household with twenty cats.

Option 3: Chemical Abortion. There are a number of drugs on the market that will terminate pregnancy at most stages. Some drugs have nasty side effects (the prostaglandin based ones) but newer drugs on the market (Alizin) are much more humane and safe. Speak to your veterinarian about this option. This is usually the option taken by people whose dogs have accidentally mated too young or with the wrong male. Corticosteroids and Cabergoline can also be used for this purpose.

Option 4: Mismating injection. Usually given within a few hours of a wrong mating. Vets used to use estrogen for this purpose but due to the side effects (bone marrow suppression and uterine infections) have switched to the more modern mismating drugs on the market (Alizin)

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