A female dog comes in heat and is able to get pregnant every six to eight months.  Her first heat takes place when she is about six months old.  This last for about three weeks.  She is most fertile around the tenth day.  Aside from a small amount of vaginal bleeding and increased urination, the most noticeable symptom of heat may be the attention that the other dogs pay your pet. To determine when a female dog is in heat and which days that she is most fertile, a breeder will test the dogs progesterone levels. This hormone peaks when the dog has ovulated.  This helps the dog owner know when it’s the right time to breed the dog.

The only thing that you may need while your dog is in heat is a pet stain remover.