Why Are My Dogs’ Nipples Enlarged After Heat? A Simple Guide

The heat cycle is a normal process happening in every female dog. And it can be a cause of many visible changes. So you might have wondered, why are my dogs’ nipples enlarged after heat?

Enlarged nipples in dogs after heat may be due to hormonal changes. It’s a normal part of the reproductive cycle that lasts for a limited amount of time. But if this condition persists, there may be other nefarious causes.

What causes enlarged nipples in female dogs after heat?

During the end of the heat cycle, high levels of progesterone are made. The hormone progesterone has a big effect on the size of the nipples of female dogs and causes them to become larger. The heat cycle is different in every dog. For example, the heat cycle of Corgis repeats every 6 months, or twice per year.

Dogs in heat will also experience behavioral changes like enhanced affection or aggressiveness. They may also lick their vulva and nipples more, or urinate more frequently. But the reason for a dog’s breast swelling post heat cycle might be more serious than this.

Can pregnancy lead to enlarged nipples in dogs?

Pregnancy is a process during which there are severe hormonal changes in the dog that will lead to notable physical differences. “When your dog is in the first few weeks of its pregnancy it can be hard to notice anything different about the behavior and physical demeanor. But, during this time they may vomit or have a decreased appetite. On average, dogs can be pregnant for approximately 62-64 days however, the exact dates will vary depending on your dog’s breed and other factors.”, according to the Michigan Avenue Animal Hospital.

The nipples will become larger and pronounced due to the higher blood flow that develops. This is because they are preparing themselves for when the mother gets to feed the pup. Besides enlargement, the nipples will change color and become more sensitive to the touch. Some pregnant dogs may also experience nipple discharge, which is entirely normal as their body prepares for lactation.

What is false pregnancy, and how does it affect nipples?

Pseudopregnancy, pseudocyesis, or false pregnancy is another reason for dog nipple enlargement after heat. It happens when the body goes through similar physiological changes that mimic pregnancy. Other signs of pregnancy like lethargy and nipple discharge can also be noticed. The dog may also leave odorless wet spots around the house. However, actual pregnancy has not occurred.

Usually, there is a change in the hormones prolactin or progesterone that affects the size of the dog’s nipples. A change in the environment of the dog like changing the home, or bringing in a new pet can also be a cause. Another suspected reason is stress in dogs. 

An article on the UC Davis School of Veterinary Medicine site says this about the condition:

Pseudopregnancy can also be acutely induced by spaying a dog near the end of estrus. Spaying removes the source of progesterone (the ovaries) and induces a rise in prolactin. The incidence of pseudopregnancy induced by spaying a dog in heat can be reduced by delaying the surgery for 8-10 weeks after the end of estrus.

What is mammary hyperplasia, mammary tumors, and mastitis?

This is a condition where the mammary gland tissue grows excessively. It is usually caused by some problem with the hormones. It is more common in female dogs that have not been spayed. It can increase the risk of a dog developing cancer in the future.

Mammary tumors are another reason for enlarged dog nipples post heat. They can be cancerous or benign and grow inside the mammary gland. It can be hard or soft on the touch, so you might be able to find it yourself.

Mastitis is the inflammation of the mammary gland tissue. It happens due to an infection and the risk is higher after the dog goes through the heat cycle.

Do nipples return to normal after heat in female dogs?

If everything is okay with your dog and the nipple enlargement happens due to heat, you can expect them to return to normal eventually. Expect this to happen around four to five weeks after they first become large. This can vary for every dog.

When should you be concerned about your dog’s nipples after heat?

If you notice that the nipples are not coming back to normal, you should start looking for signs of other conditions. Take a look at the nipples and notice the color and size. If something seems off, you might have a more serious problem. There may also be a discharge which can be clear, milky, or bloody. If you try touching the dog’s nipples and they react with pain, it might also indicate a more serious problem.

How to manage dog nipple swelling after heat?

Once you have monitored your dog and seen no suspicious symptoms, you should be calm to know that there is no serious problem happening.

Managing nipple swelling in dogs at home involves providing a comfortable and stress-free environment. Ensure your dog has a balanced diet, regular exercise, and access to clean water. Get your dog artificial grass for potty so your dog doesn’t pee everywhere. Additionally, gentle massage and warm compresses can sometimes help alleviate discomfort associated with nipple enlargement.

If you notice any serious problems with your dog, you will have to contact your veterinarian and ask for help.

Why is it significant to consult a veterinarian for persistent or severe nipple enlargement?

A vet will help you find the real reason behind your dog’s enlarged nipples. They will examine your dog and look for signs that indicate disease. Then, they will run diagnostic tests like blood work and imaging. Sometimes, a biopsy may be needed to confirm the diagnosis. This will help them make the decision on what the problem may be. 

Once a diagnosis is made, they will develop a treatment plan. They will prescribe some medications or decide if surgery is needed. The sooner you get your dog to a veterinary professional, the sooner you will catch the disease and treat it properly.

What steps can you take to prevent nipple issues in female dogs?

Preventing nipple issues in female dogs involves responsible pet ownership. Consider spaying your dog to avoid heat cycles and their associated changes. Regular check-ups with your veterinarian are also vital to detect and address any potential health concerns early, ensuring your furry friend’s long-term well-being.

Why are my dogs’ nipples enlarged after heat? – Final thoughts

The heat cycle in female dogs is a normal thing that happens a few times during the year. It is marked by a drastic change in the hormones, which has a big effect on the dog’s physical appearance. Thus, the dog’s nipples may become bigger during this process. However, they may stay large after it passes.

In this situation, the reason may be that the dog has been impregnated. Sometimes, the dog may not be pregnant but suffering from a condition called fake pregnancy. Mammary hyperplasia, tumors, or inflammation may also cause nipple enlargement.

If you notice any signs that point to the fact that the dog suffers from this condition, you need to call your vet. They will do anything they can to properly diagnose and treat your dog.


How long does a dog in heat bleed?

The bleeding stage of the heat cycle lasts for an average of 7-10 days. This stage is known as the “proestrus” and is the period when most changes will be visible.

How long do dogs stay in heat?

The average length of a heat cycle in female dogs is around 18 days. This is also referred to as the “estrus” cycle and is the period when the dog is ready to mate with a male partner.

How to know when your dog’s heat is over?

Once your dog finishes its heat cycle, the noticeable physical symptoms will start to subside. Its vulva will become less swollen and the vaginal discharge will cease. If you are wondering “why are my dogs’ nipples enlarged after heat?”, it might have a problem.

More dog health resources

Here are a few other resources talking about dog health.

You can find a lot more information on how to keep your dog healthy on our site Dogisa!

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