Pregnant Pet Mice – How to Care for Pregnant Female Mouse?

Your pet mice will breed at crazy rates if you allow them to. Keeping male and female pet mice together is only the first step.

The mice won’t waste much time in reproducing, as the female mouse will feel the “heat” every three to five days. That means that every three to five days, the female will be ready to breed.

And once the breeding is successful, there is a short, 21-day gestation period where you need to prepare yourself for the babies. During this time, you’ll need to enable the female that she has the right kind of environment to deliver the babies safely.

In most cases, the female mice will be able to deliver the babies without much help from the owner. But, you can make their lives much more comfortable and enable them to give birth safely. Before you know it, the cage will be full of babies.

You’ll have to decide whether you want to keep the babies or give them away. The size of the litter depends; sometimes, there may be as little babies as two or three, or it can be 5, or more.

Let’s take a look at how to care for pregnant mice.

How to Tell if Your Pet Mouse is Pregnant?

During the first few days or in the first week of pregnancy, it will be impossible to tell if the mouse is pregnant just by looking at it. You might try weighing it, and you might notice a small change in the weight of the mouse.

Here are some signs of pregnancy:

  • Unusual behavior
  • Visual changes (swollen belly, weight gain, swollen nipples)
  • Might start building a nest
  • Seclusion
  • Excessive eating.

But some of the most noticeable changes will be behavioral. In the first week of pregnancy, you might notice your mouse will start to behave differently; it might become slightly more aggressive and secluded, and it will also start building a nest. Another change will be that its nipples will grow and swell.

In the second week, you’ll start to see noticeable changes in its appearance. You’ll see a small bump on their abdomen. The female mouse is also likely to become hungry and will start to eat much more. It’s separate itself from the rest, as it will prepare itself to deliver.

In the third week, the pregnancy will be clearly visible. The female will gain weight fast, and they’ll seem more restless and even more aggressive during this time. This is the time right before the delivery of the litter.

Look for these changes during the pregnancy.

How Often Can Pet Mice Get Pregnant?

Mice can breed at extraordinary rates. The gestation period, or the pregnancy, will last for about 21 days. After that, the mice can get pregnant again after just a few days or weeks. After breeding, the mice can get pregnant 5 to 10 times per year. That’s a crazy rate.

Each time they deliver, they will deliver anywhere from three to fourteen babies. On average, the litter count is 6-8, but the number can vary. And if you allow them to breed constantly, then you might have an uncontrollable population of mice. You’ll want to reduce the litter by giving the mice away or keeping females and males separate.

Once the baby mice grow up (the ones you keep), they will also start breeding. So the population of mice can spiral out of control very fast.

How to Care for Pregnant Female Pet Mouse?

Providing the pregnant female mouse is important, but she’ll be able to survive on her own. But, you can make her life much easier by following some of these steps.

  • First of all, it might be for the best to keep the pregnant mouse in a separate tank or cage. This will give her enough space and freedom to move around, and to deliver in peace. Later on, the babies will be safe from the male mice, which can harm the babies or kill them.
  • Provide the mum mouse with enough nesting materials needed to build a proper pregnancy nest. You can put some cotton wool into the tank, or even toilet paper. Avoid fabric, which can get stuck onto the baby mice.
  • Provide the pregnant mother with enough food, and high-quality foods at that. This means fruits, vegetables, seeds, greens, and also cheese or other types of food. Make sure it gets enough proteins, so you can include soy milk, porridge, or even baby food.

What to do When Your Pet Mouse has Babies?

Once the pregnant female delivers the litter (after about 21 days), you’ll have to decide what to do with the babies. If you want to keep them all, that’s fine, but you’ll have to help the mother with care, and keep the males away.

If the litter is too big and you don’t want to keep all of the babies, then you have a problem at your hands. You can give away the babies, or you can contact your local shelter and ask whether they will accept the baby mice. Or, you can keep them and care for them in a separate cage.

As we have already noted, you’ll want to control the mice population, or else you could be in with a big problem. Overpopulation might occur fast.

Can You Keep Two Pregnant Mice Together?

You can if the cage or tank is large enough, but I wouldn’t recommend it. The pregnant mice and their babies need plenty of space to live comfortably.

That’s why it’s better to keep two pregnant mice separate in their own cage or tank. It’ll massively reduce stress and enable better living conditions for the pregnant mice and the babies later on.


Your pet mice are excellent breeders. They will deliver babies 5-10 times per year if you allow them to. That’s why you’ll have to be cautious of this, and keep males and females separate if needed. If pregnancy does happen, though, you can do a lot to help your pregnant mouse deliver the babies.

avatar Jane
Jane is an experienced animal care specialist with a focus on rodents and small mammals, with over 10 years of experience in the pet industry. Her articles provide practical guidance on choosing the right pet and managing common health issues. Jane is an advocate for animal welfare and supports organizations dedicated to protecting wildlife. read more...

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