Dog Contraceptive Injections and Dog Castration?

Here are a couple of possibilities in case you don't want your female dog to conceive:

• observe and close her in a room in the days that she's in heat.
• hormonal treatment in form of injections or compressed into tablets. Give her one of these every 4-5 months, depending on the dog and how often she's in heat. For more information on the matter, consult with your veterinarian.

Castration (retrieval of ovaries) would be the solution in the case that your dog has false pregnancies or actual unwanted pregnancies very frequently. Now a days this procedure is a very common one and a lot of veterinarians are doing this before the dogs' first cycle begins. Psychologically the animal does not feel the changes in it's body, therefore sicknesses such as uterus and mammary senility and false pregnancies. 

Hygiene in the Treating of Your Dog