Yorkie in season

Question
How long does a 6 lbs Yorkie stay in heat and how often do they come in heat?
We cannot neuter our little Carly who is 1 year this month due to a heart problem so we need to know what to expect.She has been in season one other time which seemed to be one output we found on quilt and that was it. Now today she is bleeding a small amount but I don't know what to expect. Can you estimate for us?  length (how long lasting). Thanks, Barbara

Answer
Proestrus normally lasts from 4 to 9 days and is when you first see bloody discharge (in some toy breeds, you won't see much.  At this point, the bitch will not accept a male.

In estrus, the discharge is more yellowish and that lasts for 4 to 14 days. The bitch may hold her tail to the side, and she would accept a male for mating, and be able to conceive puppies.

A bitch is "in season" for 21 days.  Roughly 1 week coming into heat, 1 in heat and one going out of heat.  Be sure to confine your female dog the whole 21 days.  Remember that males can smell a bitch in heat from quite a distance and they will "move heaven and earth" to get to her.