When do female pugs start their first menstrual cycle?

Most dogs menstruate (come in season) approx every 6 months and the first time can be any time from about 7 months of age, They bleed for about 2-3 weeks. It can be less frequently, especially with Pugs, one of my Pug bitches had her first season at 11 months old and comes in season only every 11 months.