How Long Do Female Dogs Stay in Heat?

Skylar Dial
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Question: My female puppy is in heat. How long will it last?

Answer: The duration of a dog’s heat cycle can vary. Each dog will have her own unique cycle, with heat lasting anywhere from three days to a little more than a month … and yes, I’ve read about some dogs that have been in heat for almost a year! The American Society for the Prevention of Cruelty to Animals (ASPCA) told a similar story about a neighbor’s dog, which was in heat for six full months. That may be an outlier dog, and the ASPCA other wise recommends spaying dogs for a number of different health-related reasons.

Dogs that have been spayed typically don’t go into heat. And it’s not just about preventing heat cycles. Spaying your dog can be recommended based on her specific medical history and risk factors.

In some cases, a dog in heat can be very difficult to live with. She may not settle into her bed and will go back to it repeatedly. She might learn to open the refrigerator and help herself to human food. She might cry a lot and lose interest in playing with her toys, let alone with her family. She can be restless and destructive, too.


How long do female dogs stay in heat?

The female estrous cycle (season when female is fertile) starts when a female is approximately six months old, and ends around the age of 10 – 14 years old. Adult dogs in general typically come into heat every six months although this cycle can vary depending on breed and other factors. Female dogs that are spayed early in life can still show heat cycles but they tend to be less frequent.

A dog's cycle usually lasts between 21 and 45 days, but a dog can be in heat for just a few days out of every six months. The average heat cycle lasts approximately seven days.

A female dog will cycle approximately every six months starting in her adolescent years until around the age of 10 – 14 years, when the uterine system begins to shut down. If the female dog is spayed after 7 years of age she will most likely not cycle again. A non-spayed dog, as she approaches the end of her cycle will probably be interested in breeding with any male dog.

The 4 Phases of the Canine Estrus Cycle:

Dogs go into heat every six months for about 3-4 days at a time. The entire estrus cycle takes about 9-11 weeks and is regulated by hormones. There are four different stages of the cycle. Read on to find out when your dog is most likely to get pregnant, how to tell if she is pregnant and what to do if you are interested in breeding.

After your dog reaches a year of age, this normal canine estrus cycle begins. You may hear it jokingly referred to as "doggie PMS". They are a lot like humans in that the estrus cycle begins between the ages of 6 months to 3 years. Typically dogs will first start their cycle around 6 months of age. The first cycle will be shorter in length and can be as short as 3 weeks.

A fully grown female will come into heat or estrous receptivity every 6 months on average. This is about 3-4 days in length. The estrus cycle is typically around 30-45 days long. After the eggs are released, they can be fertilized for the next 10-12 days, which is the oestrus period. A female will have an obvious vaginal discharge during this time. The eggs will need 21 days to remain fertile through ovulation. If the female is not bred during this time, the eggs will die and it is necessary to wait another cycle to get pregnant.