The onset of a normal breeding season begins when the vulva starts to increase in size, and the bitch may urinate more frequently and in more than the usual places. When the first show of color or bleeding from the vulva is apparent the bitch has come into season. There will be a marked swelling of the vulva as the color of the discharge deepens. This section of the season (heat) can last from a few days to two weeks and generally the bitch is not able to conceive during this phase. It is not until the discharge changes to a straw or clear colour and the vulva begins to soften that the signals point to imminent acceptance of mating.