Lab in Heat

Question
I have a female labrador dog, and she in heat. How long does this last, a week or more?

Answer
It trails off and it is hard to say when it is finish.  The second and third weeks are when the most risk of accidental breeding is. Don't take this lightly. She will do anything to get loose and get to a male. Once loose, an accidental breeding and an unwanted litter is far from the worst that can happen. Such breedings can also result in fatal infections. She can get killed when she dashes heedlessly across the road in front of a car. Other dogs or coyotes may kill her.

You can expect the same thing about every 6 months for the rest of her life if you don't go ahead and get her spayed. There is no other answer, and no good reason not to. Besides saving the hassles, it reduces the chances of cancer later in life. Please make life easier for yourself, her, and society in general by getting her spayed as soon as a vet will do it.