Female dogs typically go into heat, or have their "periods," about twice a year, roughly every six months. However, this can vary depending on breed and individual dog. Small breed dogs may cycle three to four times per year, while giant breeds might only cycle once a year
. The heat cycle usually lasts between 2 to 4 weeks, with the most fertile period around day 10. During this time, female dogs may have vaginal bleeding or discharge, but this is different from human menstruation because dogs do not shed their uterine lining monthly
. Female dogs generally reach puberty and have their first heat cycle around six months of age, though this can range from as early as four months in small breeds to up to two years in large breeds
. In summary:
- Heat cycles occur about every 6 months on average.
- Small breeds may cycle more frequently (3-4 times/year).
- Large breeds may cycle less frequently (once per year).
- Each heat cycle lasts 2-4 weeks with bleeding primarily at the start.
- Dogs do not have monthly periods like humans but have estrous cycles instead
