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When will my dog have her first heat and what are the signs?

Updated on September 23rd, 2025

Pet's info: Dog | Siberian Husky | Female | unspayed | 9 months and 19 days old | 35 lbs

Why hasn't my dog had her first heat yet and how will I know when she has it

3 Answers

Most Helpful Answer

Answered By Laura Johnson VMD

Veterinarian

Published on September 4th, 2017

Hi, thanks for using Petco Pet Education Center, formerly Petcoach!

A dogs first heat is some what genetic and breed related. Toy and small breeds may have their first heat at 6-8 months while larger breed dogs like Great Danes may not have their first heart until 18-24 months. I have a client who's lab still didn't have their first heat by 1 year of age. I would expect that Bella at 9 months should have her heat very soon or with in the next 3-6 months.

Dogs act slightly off when they are in heat. The vulva becomes prominent and swollen. Then you will see bloody fluid from the vulva. Dogs tend to lick a lot.

I hope this helps!

3Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Laura Johnson VMD
Veterinarian
Hi, thanks for using Petco Pet Education Center, formerly Petcoach!

A dogs first heat is some what genetic and breed related. Toy and small breeds may have their first heat at 6-8 months while larger breed dogs like Great Danes may not have their first heart until 18-24 months. I have a client who's lab still didn't have their first heat by 1 year of age. I would expect that Bella at 9 months should have her heat very soon or with in the next 3-6 months.

Dogs act slightly off when they are in heat. The vulva becomes prominent and swollen. Then you will see bloody fluid from the vulva. Dogs tend to lick a lot.

I hope this helps!
3Pet Parents found this answer helpful
Answered By Rodrigo Roca, DVM
Veterinarian
Published on January 11th, 2020
Hello, yes most dogs have their first heat cycle between 7-10 months of age. It does vary between pet and she may be one to have her first heat cycle later in life. Some pets may undergo their first heat cycle unnoticed by owners. Common signs of entering a heat cycle includes bleeding from their vulva as well as nursing and mounting behavior. If you note any of these she’s likely entering her heat cycle.
1Pet Parents found this answer helpful

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Related Questions

When will my 6-month-old dog get her first heat? What are the signs?

Hi and thanks for posting! Signs of heat in dogs include swollen vulva, red tinged discharge from the vulva, licking near her vulva, and sometimes mounting other dogs or inanimate objects. Standing to be mounted by another dog is also another sign to watch out for. Typically, a female dog's first heat will be around 6 months-1 year of age and can occur at a later age in large breed females. Dogs come into heat twice a year- once in the spring/summer and once in the fall/winter. I hope this helps and thanks for using Petco Pet Education Center, formerly Petcoach!

Updated on September 23rd, 2025

Female dog in heat: How long does she bleed, what's normal, & worry?

Hello and welcome to Petco Pet Education Center, formerly Petcoach. Dog's heats will last a variable amount of time from animal to animal. Some will last a few days, and some can last up to 3 weeks. Most will be on average around 7 days long. A fair amount of blood coloured fluid will be produced, however dogs are pretty good at cleaning themselves up. About 1 month after she has finished bleeding, I would talk to your vet about getting her desexed to prevent pyometra (pus filled uterus), decrease her risks of mastitis, and many different types of cancers, and prevent unwanted pregnancies. Best of luck with Bella!

Updated on September 23rd, 2025

Training & Behavior

How do I handle my dog's first heat cycle and what should I expect?

Thank you for submitting your question! Most puppies will start their first heat cycle anywhere from about 6-10 months of age. It can last upwards of 18-21 days. You will notice swelling of her vulva and mammary chain. She will spot and bleed as well. Some dogs keep themselves very clean and you only see small amounts of discharge, others will require diapers. You may observe some behavioral changes as well. These can include a decreased appetite, attraction to male dogs or being more clingy to you. Most dogs will cycle every 6-9 months with small dogs cycling more frequently and giant breeds less. I hope this information helps!

Updated on September 23rd, 2025

When does a large breed dog typically go into her first heat?

Average age for the first estrus in a large breed dog is about 6-9 months of age. It is not usual for large breeds to not have their first heat until somewhere between 12 and 18 months of age. So, as you can see, it varies widely when a large breed dog may go into heat for the first time. Some dogs come into heat and don't outwardly show any signs so you may not even notice their heat cycle. My best recommendation is that if you have a breeding bitch that is 18-19 months old and she has not had her first heat cycle, you should have her evaluated by a reproductive veterinarian to make sure she is sound for breeding. Hope this helps. Best wishes.

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Training & Behavior

Why is my 15-month-old chihuahua acting weird? Is it her first heat?

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. If she has not had her first heat cycle then this could certainly be the cause of what you are seeing. If these signs do not resolve after 2-3 weeks, then I would recommend having a veterinarian take a look at Belle so that the most appropriate diagnostic and treatment recommendations can be made. Please let me know if you have any other questions or concerns and I would be more than happy to help you further.

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Health & Wellness

How old does a female dog need to be to have her first puppies?

Hello and thank you for reaching out to Petco Pet Education Center, formerly Petcoach. An intact female dog, depending on the size and breed, will likely have her first heat cycle between the ages of 6 months and 18 months. If she were bred at that first cycle, she should give birth approximately 63 days after this mating. I hope this is helpful!

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My dog is bleeding, is she in heat? How do I manage her period?

Thank you for submitting your question regarding Odesia. When a dog comes into heat, her mammary chain and vulva will swell. She will have a blood tinged discharge. A heat cycle lasts approximately 18-21 days. Spaying her prior to her first heat cycle will prevent this from occurring. Most dogs come into heat for the first time around 7-10 months of age with larger breeds starting their cycles later. If she goes into heat, doggy diapers with a feminine hygiene pad are an easy way to keep her clean. I hope this information helps!

Updated on September 23rd, 2025

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