How old are chihuahuas when they stop having menstrual cycles?

Chihuahuas, like other dogs, typically experience their first estrous cycle (heat) around six months to a year of age. They usually have heat cycles twice a year, and while there's no specific age at which they definitively stop having menstrual cycles, many female dogs will go through their last heat cycle between the ages of 8 to 12 years. Factors like health, breed, and individual variation can influence this timeline. Spaying can also eliminate menstrual cycles altogether.