Can Cats Be In Heat While Pregnant? – Interesting Facts

Cats are highly fertile animals and parents with queens may wonder if they can go into heat (oestrus) whilst they are already pregnant.

Biologically, their bodies are designed to prevent such an occurrence from happening.

Queens go into heat to mate and get pregnant. Once this happens, hormonal changes occur to halt oestrus cycles and prepare a queen’s body to carry a litter.

Can cats go into heat when pregnant

Living systems are complex, however. There are always exceptions to any biological function, including the reproductive system of our feline companions.

In some instances, it is possible for queens that are already carrying a litter to be in heat again.

How Queens Can Be Pregnant And In Heat

If you observe your cat in heat while pregnant, one of four things may be occurring.


The breeding seasons of cats can range anywhere between 6 months to all year round.

This depends on the temperature and amount of light they are exposed to.

During these periods, queens go into heat (oestrus) multiple times in a cyclical fashion.

Each oestrus cycle lasts three weeks on average, even if a queen falls pregnant early into the process.

When queens are in heat, they typically mate multiple times and with various males. Cats are induced ovulators, so egg release is stimulated by mating.

Therefore, each mating event within an oestrus cycle can lead to pregnancy, which can result in superfecundation.

Superfecundation is the fertilization of 2 or more eggs by different males during the same oestrus cycle. It produces a litter of kittens with different fathers.

Superfecundation is a common occurrence in cats, especially in unspayed females that roam freely.

Consequently, it may be hard to know if kittens born by a queen at the same time have the same father.

Hormonal And Physiological Changes That Result In Oestrus Later In Pregnancy

In sporadic instances, your queen can go into another heat cycle while pregnancy is well established.

This leads to the birth of multiple litters in short succession. The causes of such situations are unclear and not well studied.

They are likely the result of physiological and hormonal abnormalities that affect reproductive cycles.

False Pregnancies

When queens go into heat, one of three things can happen. They:

  • They mate and fall pregnant, then come back into heat after giving birth.
  • Do not mate and come back into heat a few days after an oestrus cycle ends.
  • Mate, but do not get pregnant and experience pseudo (false) pregnancies. They exhibit all the signs of pregnancy, including getting swollen abdomens and producing milk. No kittens are born, and queens typically return into oestrus within 4 to 6 weeks. False pregnancies are rare in cats. They are thought to be caused by imbalances of the hormones prolactin and progesterone.

The only way to differentiate between real and false pregnancies is to have veterinarians conduct ultrasound or x-ray tests.

Accordingly, if a queen is displaying unconfirmed pregnancy symptoms, and it goes into heat again, it may have had a false pregnancy initially.

Other Causes

A female cat that displays pregnancy symptoms then goes into heat may not be pregnant or having a false pregnancy initially.

In some instances, illnesses and diseases like tumors and worm infestations cause their abdomens to expand.

Such conditions need to be medically addressed, especially if the queen does become pregnant.

They can be dangerous situations for both the mother and kittens. Disease spread, kitten deformities, and death can all be possible outcomes.

Keeping Queens Healthy

Other than superfecundation, most biological states that cause queens to appear as if they are both pregnant and in heat are usually due to hormonal imbalances.

Hormones are part of the endocrine system. They are necessary for controlling many body functions, including reproduction.

Hormone imbalances occur when they are either overproduced or under-produced.

They lead to endocrine disorders where bodies do not function normally.

Hormone imbalances are often caused by underlying conditions such as cancers and infections in the endocrine system.

If your cat is diagnosed with a hormonal condition such as a false pregnancy, it is vital to get her screened.

Screening helps to identify the underlying causes so that appropriate treatments can be given.

Additionally, oestrus and pregnancy symptoms can both be uncomfortable for cats when they occur independently.

If they take place at the same time, the effects can compound and cause greater distress to a queen.

To avoid such situations from occurring, it is necessary to monitor the behaviors of female cats that are suspected to be pregnant.

They must get adequate professional veterinary care and checkups.

Providing For Queens And Kittens

It is almost impossible to discuss cat reproduction without discussing the distressing issue of cat overpopulation and how it is addressed.

Cats are infamously fertile animals that have been praised by many cultures as fertility deities.

They start to breed from a young age, with female cats becoming sexually mature at about 6 months of age.

Unless they are spayed, queens remain fertile and able to birth kittens throughout their lifetime.

On average, this is about 4 years for outdoor cats. Indoor cats can have particularly long lifespans of about 17 years on average.

Additionally, cats can have up to 5 litters of kittens in a year.

They have gestation periods of about 65 days, and they can re-enter oestrus soon after giving birth.

All these factors have led to a colossal feline overpopulation crisis the world over.

Sadly, it is addressed by euthanizing millions of cats annually because there are not enough homes and shelters for them.

To be accountable cat parents or breeders, it is imperative to keep reproductive females only if we can provide for them and their litters.

Otherwise, it is best to get them spayed by qualified veterinarians. Spaying also has added advantages.

It minimizes the chances of female cats developing certain cancers of the reproductive system like ovarian cancer.

Similarly, unspayed females cannot suffer from infections of the reproductive system.