Feline Mismating: Pregnancy Diagnosis and Clinical Management

Mismating or unplanned mating is a common clinical problem in sexually mature queen cats because of their free-roaming nature. Consequently, medical termination of pregnancy may become a frequent request from owners^1,2. When an unintended mating occurs, the immediate clinical priority is to establish whether mating was successful, assess the possibility of pregnancy, and determine the stage of pregnancy before discussing further management. 

The queen’s reproductive status should be assessed systematically because mating during estrus has a high likelihood of resulting in conception. The queen is an induced ovulator; mating triggers a peak LH surge, which subsequently induces ovulation and fertilization. 

Recognizing Estrus and Suspected Mating 

When an owner reports an unplanned mating, the history should focus on whether the queen was in estrus and when the mating occurred. Relevant estrus-associated signs include^1,3: 

• Vulvar swelling and sero-sanguinous vulvar discharge 

• Increased proximity toward males and increased vocalization 

• Excessive grooming and rubbing of the head 

• Lordosis behaviour 

If mating occurred while the queen was in estrus, pregnancy should be considered a realistic possibility. The date of mating should be documented because it helps establish the appropriate timing for subsequent pregnancy assessment. 

Confirming Successful Mating¹ 

Mating may not always be witnessed by the owner. In such cases, vaginal smear examination can be used to assess the presence or absence of spermatozoa. The presence of spermatozoa, together with failure to return to estrus within 14–28 days, indicates that the queen may be pregnant. 

Clinical signs may also raise suspicion of pregnancy. These include increased appetite, abdominal enlargement, absence of estrus signs, weight gain, morning sickness, mammary gland enlargement, and mating behaviour. However, these findings should not be used as the sole basis for confirming pregnancy. 

When mating has not been witnessed, the reproductive history and clinical findings should therefore be followed by appropriate diagnostic confirmation. 

Ultrasonographic Pregnancy Confirmation¹ 

Whether the owner witnessed mating or not, an ultrasonographic examination should be used to confirm pregnancy approximately 25–30 days after estrus. This timing also provides an opportunity to establish the stage of pregnancy, which is important when considering any subsequent medical termination. 

The date of mating and ultrasonographic examination are therefore central to clinical decision-making. Before proceeding with medical termination of pregnancy, the owner should clearly understand that management differs according to whether the queen is in the early, middle, or later stages of pregnancy. 

Establishing the Pregnancy Stage^1,4 

Queen cats have a gestation period of approximately 60–65 days. Progesterone plays an important role in maintaining pregnancy and is produced by the corpora lutea during pregnancy. In queen cats, the placenta produces progesterone after approximately 40–50 days of gestation independently of the corpora lutea. 

This change in progesterone production is clinically relevant when determining the suitability of different approaches to pregnancy termination. Therefore, treatment decisions should not be made solely on the assumption that all mismated queens are at the same stage of pregnancy. 

Practical Management of a Mismated Queen 

For a queen presented following suspected mismating, a practical clinical workflow is: 

1. Establish whether the queen was in estrus at the time of possible mating. 

2. Record the date and circumstances of mating. 

3. If mating was not witnessed, consider vaginal smear examination for spermatozoa. 

4. Monitor whether the queen returns to estrus within 14–28 days. 

5. Assess reported clinical signs that may suggest pregnancy. 

6. Confirm pregnancy by ultrasonography approximately 25–30 days after estrus. 

7. Determine the gestational stage before discussing medical termination. 

If the owner does not intend to breed the queen or raise kittens, ovario-hysterectomy can be considered as a permanent reproductive management option for preventing estrus and subsequent mismating. 

Avoiding Unnecessary Intervention 

When mating has not been confirmed, unnecessary exposure to therapeutic agents should be avoided. The owner may be advised to wait until pregnancy has been confirmed, thereby reducing unnecessary costs and potential treatment-related adverse effects. 

The key clinical principle is to confirm the reproductive status before intervening. A careful mating history, recognition of estrus, vaginal smear examination when appropriate, and timely ultrasonographic confirmation provide the veterinarian with the information needed to determine whether pregnancy is present and establish the appropriate clinical management pathway. 

References 

1. Sunil P, Singh K, Biswas N, Kumar S, Dwivedi P, Srivastava N, Khan MH. Medical Termination of Pregnancy in Queen. Animal Reproduction Update. 2024 Jul 1;4(2):19. https://www.researchgate.net/profile/Sunil-Parmar-7/publication/384226126 

2. Eilts BE. Pregnancy termination in the bitch and queen. Clinical techniques in small animal practice. 2002 Aug 1;17(3):116-23. https://doi.org/10.1053/svms.2002.34325 

3. Johnson AK. Normal feline reproduction: The queen. Journal of feline medicine and surgery. 2022 Mar;24(3):204-11. https://journals.sagepub.com/doi/pdf/10.1177/1098612X221079706 

4. Holst BS. Feline breeding and pregnancy management: what is normal and when to intervene. Journal of feline medicine and surgery. 2022 Mar;24(3):221-31. https://journals.sagepub.com/doi/pdf/10.1177/1098612X221079708