Unwanted mating (misalliance)

Misalliance / mesalliance is the term used when a female dog is in season and has a mating that is not wanted by the owner. Dogs have high fertility and after a successful mating 8 out of 10 bitches will get pregnant. In the world there are already many unwanted dogs and it is a big commitment to have a litter of puppies that you did not plan, and even harder to find good homes for them all. If your bitch has been mated unintentionally contact your veterinarian as soon as possible as they may be able to prevent her having puppies.  

©Pixabay / Pexels

If you have seen your dog being mounted by a male dog when she is in season there is a chance that she may be pregnant. Some dogs may behave differently within a few days of mating – but this can occur whether or not she is actually pregnant. At first there will be no physical changes in your dog so it would be very difficult to know whether she is pregnant until around 40 days when some swelling of the tummy may be seen. However, in first time mothers, and those carrying a small number of puppies, there might not be any change in her shape until the puppies are born. Swelling of the nipples and mammary glands can occur around 30 days after mating, but again this can also happen in dogs whether or not they are pregnant. If you don’t want a litter of pups it’s best to take your dog to your veterinarian before the time when a pregnancy is obvious.

Your veterinarian may take a smear from your dog’s vagina if the suspected mating occurred within the last 3 days. By examining the kind of cells found your vet will be able to tell at what stage of the cycle your dog is in and therefore whether she could get pregnant during that time. In most cases, if mating has happened recently, sperm will be seen in a smear. Treatment will often be offered at this time before the pregnancy has become established.

Your veterinarian can confirm a pregnancy with either a dog pregnancy test, which measures blood hormone levels, from days 21-25 after mating, or by ultrasound from about day 20-22. It is also possible to provide the treatment at this time.

The best way to prevent unwanted pregnancy in female dogs is to have your dog spayed. If you think your dog has been mated although you had planned to have her neutered, it is still possible to continue with the procedure as long as this is done shortly after mating. The means the surgery will be performed straight after her season; at this time the surgery is not significantly more risky than when performed at the normal time.

If for some reason you don’t wish to have your dog neutered, for example if you might want to have a litter of puppies in the future, and you fear she may have been mated unintentionally, you can ask your veterinarian to give an injection that will end the pregnancy. This is best given in the first 3 weeks after mating.

In dogs, pregnancy only continues in the presence of the hormone progesterone. An injection of a drug that acts against progesterone will cause the pregnancy to terminate. An anti-progesterone injection can be given between 0 and 45 days after mating (but as noted above is best if given in the first 3 weeks). Two injections are given 24 hours apart. If the drug is given in the first few days after mating it can prevent implantation so that pregnancy never occurs. If it is given later then abortion occurs (usually within 3 days of injection) and this can result in expulsion of fetuses (this is the reason that earlier treatment is preferred). A veterinarian should check your dog at approximately 28 days after mating to make sure the pregnancy has ended.

Unfortunately, the injection can have a number of unpleasant side effects including depression, loss of appetite and a vaginal discharge which can be clear or brown. If the injection is given in late pregnancy, then abortion occurs, and your dog may show signs of labor. In a few cases not all the puppies will be expelled and further treatment may be needed. This is why it is very important that a dog is checked by your veterinarian again after treatment to ensure all the puppies have been removed.

Dogs treated with an anti-progesterone injection may come in season quickly again (1-3 months later) and care needs to be taken to ensure they don’t get unintentionally mated again.

If your dog has been mated by accident then you should see your veterinarian as soon as you can to discuss the options. It is possible to prevent unwanted puppies but the earlier you seek help the safer it will be for your dog.