When to see a vet urgently
Do not wait for a reproductive appointment if your cat develops:
- pus-like or abnormally bloody genital discharge;
- marked tiredness, loss of appetite or vomiting;
- abdominal enlargement or pain with deteriorating general condition;
- increased drinking and urination in an unwell, unspayed female.
Pyometra, an infected uterus, can be life-threatening even without visible discharge. You can find a vet near you.
Overview
Failure to become pregnant or carry kittens can result from hormonal disturbances, anatomical abnormalities, infections or other factors. Infertility has two main types:
- Primary infertility: the cat has never been able to reproduce.
- Secondary infertility: reproduction previously succeeded but later became impossible because of disease or another cause.
Investigation distinguishes disrupted oestrous cycles, unsuccessful mating, failure of fertilisation and pregnancy loss. A male may have difficulty mating and transferring sperm to the female, or problems with sperm production and quality. One mating without a resulting pregnancy does not establish permanent infertility.
The female is not automatically at fault simply because the problem becomes apparent when she has no kittens. Both animals' health and reproductive history are assessed. A previous litter shows that reproduction once succeeded but does not rule out later disease or a problem involving the current pair.
Causes
The most common causes of infertility in cats include:
- hormonal disorders, such as ovarian cysts or impaired ovarian or testicular function;
- infections involving viruses, bacteria or fungi, for example herpesvirus or chlamydia;
- congenital reproductive organ abnormalities;
- unsuitable living conditions and stress;
- unfavourable mating circumstances, including timing within oestrus and behavioural factors;
- age-related changes.
The importance of infection varies with the organism. Feline parvovirus and retroviruses can damage pregnancy, for example, but the specific role of herpesvirus and chlamydia in infertility is less clear. A previously identified infection therefore does not establish the cause of the current problem. Nor does precautionary antibiotic treatment for every cat resolve a reproductive disorder.
Risk factors
- Cats older than 7–8 years.
- Animals with chronic illnesses.
- Cats living in stressful conditions.
- Lack of preventive protection against infection.
- Breeding animals without health checks.
Age is not a single dividing line between fertility and infertility. Changes in the uterine lining and certain other diseases may become more important with age, for example. However, research on the frequency of different feline risk factors is limited, so the list is not a precise risk calculator or a reason to leave a young cat unexamined.
Day length affects a female's oestrous cycle. Low light can explain an absence of seasons, while indoor lighting can alter seasonality. Distinguishing a young cat that has not reached puberty from an adult with a cycle disorder also matters. Conversely, an owner may miss signs of oestrus despite normal ovarian activity.
Symptoms
Signs of infertility vary:
In females:
- absent or irregular seasons;
- failure to become pregnant despite repeated matings;
- miscarriages or embryo resorption.
In males:
- reluctance to mate and reduced activity;
- low-volume or poor-quality semen identified during veterinary investigation.
A male's reluctance to mate does not alone indicate semen quality. Pain, illness, inexperience, fear or unsuitable surroundings can prevent mating. A structural problem with the testes or penis may also impair reproduction despite otherwise apparent health. Examination is performed safely; do not try to examine or correct genital problems at home.
Early embryo loss may go completely unnoticed. You may interpret this as the female never having become pregnant. The vet therefore asks whether pregnancy was actually confirmed or assumed from abdominal or mammary changes. Ultrasound monitoring helps distinguish these situations.
Consequences
Infertility itself does not threaten a cat's life, but may indicate underlying disease. Possible consequences include:
- chronic genital infections;
- hormonal disorders;
- deteriorating general health from untreated disease;
- loss of breeding value.
A common, readily correctable reason for apparent infertility is the cat's ovulation pattern: eggs are usually released only after mating, and a single mating is often insufficient. During oestrus, cats mate several times, usually 3–4 times over 1–2 days; otherwise ovulation may not occur at all.
Mating normally triggers ovulation, or egg release, but spontaneous ovulation without mating can also occur. The mating numbers above do not guarantee pregnancy or justify forcing the animals. Allow rest and opportunities to withdraw; pain, fear or fighting ends an attempt. When a disorder is suspected, hormonal testing can assess ovulation rather than simply repeating matings.
Diagnosis at the vet
To investigate infertility, the vet may perform:
- a general health examination and history;
- blood tests to assess hormone levels;
- ultrasound of pelvic organs;
- semen examination in males;
- tests for viral and bacterial infections.
Bring notes about seasons, observed matings, partners and previous litters. Explain how pregnancy was confirmed, any losses and kitten abnormalities. Illnesses, medicines, diet and reproductive outcomes in other household cats also belong in the history. This helps show whether the problem affects one cat, one pair or the whole breeding environment.
Ultrasound in a female examines the uterus and ovaries. It may reveal fluid accumulation, cystic lining changes or an ovarian lesion, for example. Vaginal cytology helps assess cycle stage and inflammation. A progesterone sample can indicate ovulation, but interpretation depends on timing and does not alone confirm pregnancy.
In males, the testes, scrotum and, when needed, penis are examined alongside general health. Semen assessment includes sperm number, movement and structure. If no sperm are present in a collected sample, unsuccessful collection may also be responsible. Confirmation may therefore be needed. Interpretation of feline semen also has limitations in research and reference values.
Infection tests follow symptoms and transmission risk. Even normal animals have bacteria on genital mucous membranes, so a positive culture alone does not prove disease or a need for antibiotics. Sometimes a reproductive specialist, biopsy or chromosome test is needed. Not every animal receives every test at once.
Treatment and prognosis
Treatment targets the identified cause. Unsuitable mating conditions may be corrected through a calm, safe environment and cycle assessment. Inflammation, pain and systemic illness are treated before further attempts. Hormonal treatment is not a universal solution, and you should not try hormones or mechanically inducing ovulation at home.
An anatomical lesion may require surgery. Severe pyometra may require stabilisation and removal of diseased reproductive organs, even though fertility is lost. Breeding wishes must not delay treatment of a life-threatening disease. A suspected inherited finding also affects whether restoring fertility is an appropriate goal at all.
Temporary systemic illness can reduce a male's semen quality, and improvement may not be immediate. Fever, for example, can impair sperm production without a separate genital defect. Permanent testicular damage or a significant structural abnormality may prevent reproduction despite treatment. Some cats have no identifiable cause or effective treatment. Prognosis therefore depends on the overall picture and follow-up investigations when needed, rather than one laboratory result.
During treatment, monitor agreed factors: general condition, weight, seasons and any pregnancy's progress. Further mating is agreed only after results and recovery are assessed. If a cat is not intended for breeding, restoring fertility is not itself necessary. Any underlying disease still needs treatment, and appropriate prevention of reproduction is discussed with the vet.
Prevention
Preventing infertility relies on general healthcare:
- regular veterinary checks and reproductive organ examinations;
- vaccination to prevent infections;
- monitoring hormonal balance;
- reducing stressors;
- careful choice of breeding partners;
- balanced nutrition to support health.
Vaccination and parasite prevention are planned before pregnancy, considering each product's safety. Vaccination does not prevent every reproductive disorder, and products used at other times are not automatically given during pregnancy. New animals' health and contacts are assessed before introducing them to other cats.
Maintain suitable body condition and a balanced diet. Adding vitamins, minerals or other supplements yourself does not replace nutritional assessment. Breeding decisions also consider familial disease and previous kittens' health. Even careful care cannot prevent every case of infertility.
This article provides general information and does not replace veterinary care. If your cat develops symptoms, contact a vet.
Frequently asked questions
Does one unsuccessful mating mean infertility?
No. Mating may not have been completed, timing may have been unsuitable or ovulation may not have started. The male's role is assessed too. Repeated problems need investigation rather than forcing further attempts.
Can a cat with normal seasons be infertile?
Yes. Oestrous behaviour alone does not demonstrate ovulation, successful fertilisation or continuing pregnancy. Uterine disease or early embryo loss can prevent a litter despite apparently ordinary seasons.
Does hormonal medicine always help?
No. Benefit depends on the cause, and knowledge of treatment for feline reproductive disorders has gaps. Systemic illness, inflammation or a structural abnormality needs its own solution. A vet assesses whether hormonal treatment is justified.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
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- Breeding Management of Queens, Merck Veterinary Manual, accessed 2026-11-05.
- Infertility in Cats, Merck Veterinary Manual, accessed 2026-11-05.
- The Breeding Soundness Examination in Dogs and Cats, Merck Veterinary Manual, accessed 2026-11-05.
- Reproductive Management in Catteries: Optimising health and wellbeing through veterinarian-breeder collaboration, Journal of Feline Medicine and Surgery, accessed 2026-11-05.
- Infertility in Female Cats, VCA, accessed 2026-11-05.
- Pyometra in Cats, VCA, accessed 2026-11-05.
- 2024 guidelines for the vaccination of dogs and cats, WSAVA, accessed 2026-11-05.