The only way to do this is by spaying her. The only way to stop your dog from having a period is to get her spayed before her heat cycle starts. Unlike women, whose period starts after every 28 days, female dogs bleed for an average of 9 days during the first stage of the process, known as proestrus.  The second stage, known as estrus, is when the bleeding starts to subside. This cycle takes place twice a year, and you can stop this by getting her spayed.