Dog Period Lasts How Long. If there are two matings, make a note of the dates and expect birth to occur between 63 and 65 days later. It can be shorter or longer and you’ll know the cycle is over when all her vulva returns to its normal size and there’s no more bleeding or discharge.
You’ll know your dog has her period if she cries at the smallest things and binges on lifetime movies and chocolate m&ms (ha! It begins with mild swelling of the vulva and a bloody discharge. This stage lasts 9 weeks, or about 63 days.