General approach.

Please refer to the general discussion of Failure of Pregnancy for basic concepts.

There is little written in the peer reviewed literature about failure of pregnancy in cats.

Fournier et al (2016) reported on pregnancy failure, stillbirth and kitten mortality in France. Their statistics were based on 7075 litters and 28,065 kittens. Among pregnant queens 8.4% had failure of pregnancy. Mean litter size was 4.0 ± 1.9. 8.5% were stillborn. Neonatal and other kitten mortality rate was 8.2%. 16.0% of kittens born died before weaning.


Fournier A, Masson M, Corbière F, Mila H, Mariani C, Grellet A, Chastant-Maillard S. Epidemiological analysis of reproductive performances and kitten mortality rates in 5,303 purebred queens of 45 different breeds and 28,065 kittens in France. Reprod Domest Anim 2017; 52 Suppl 2: 153-157



Maternal disease

Pregancy related heart failure

Stoneham et al (2006) reported on a cat that developed heart failure while pregnant. After a caesarian, signs resolved and the cat lived for 9 years.


Stoneham AE, Graham J, Rozanski EA, Rush JE. Pregnancy-Associated Congestive Heart Failure in a Cat. J Am Anim Hosp Assoc 2006; 42: 457-461



Givens and Marley (2008) provide the following list of causes in cats

Givens MD, Marley MS. Infectious causes of embryonic and fetal mortality. Theriogenology. 2008; 70: 270-285



Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacterales, Family Enterobacteriaceae, Genus Salmonella


Pretzer SD. Bacterial and protozoal causes of pregnancy loss in the bitch and queen. Theriogenology. 2008; 70: 320-326.


Coxiella burnetii

There is little attention given to coxiellosis in cats, even though is a recognised that Coxiella burnetii infects the placenta of cats and causes human disease. In Canada it is known for causing pneumonia called Poker Players pneumonia, a community acquired pneumonia, for which Coxiella represents about 20%.

The prevalence of Coxiella in cats is about 8% based on epidemiological studies testing with PCR of reproductive tissues, and in about 8% of 34 cats with reproductive tract disease (8 cats) and normal cats (26 animals).

In Australia, 9 veterinary personel were infected following the caesarian section of a cat. Six of 27 cats in the cattery were serologically positive for Coxiella.

In a study of 94 dogs and 9 cats whose offsping that aborted, were stillborn or died in the neonatal period. None had Coxiella infection.


Fujishiro MA, Scorza AV, Gookin JL, Lappin MR. Evaluation of associations among Coxiella burnetii and reproductive abnormalities in cats. J Feline Med Surg 2016; 18: 344-347.

Kopecny L, Bosward KL, Shapiro A, Norris JM. Investigating Coxiella burnetii infection in a breeding cattery at the centre of a Q fever outbreak.J Feline Med Surg 2013; 15: 1037-1045

Langley JM, Marrie TJ, Covert A, Waag DM, Williams JC. Poker Players' Pneumonia. New Engl J Med 1988; 319:354-356

Stefanetti V, Compagnone A, Sordini C, Passamonti F, Rampacci E, Moscati L, Marenzoni ML. Retrospective biomolecular investigation of Coxiella burnetii and Leptospira spp. DNA in Cases of Abortion, Stillbirth and Neonatal Mortality in Dogs and Cats. Top Companion Anim Med2018 Dec;33(4):122-125.


Felid alphaherpesvirus 1 (Feline rhinotracheitis virus)

Phylum Peploviricota, Class Herviviricetes, Order Herpesvirales, Family Herpesviridae, Genus Varicellovirus, Species Felid alphaherpesvirus 1


Decaro N, Carmichael LE, Buonavoglia C. Viral reproductive pathogens of dogs and cats. Vet Clin North Am Small Anim Pract. 2012; 42: 583-598.

Feline immunodeficiency virus

Phylum Artverviricota, Class Revtraviricetes, Order, Ortervirales, Family, Retroviridae, Genus Lentivirus, Species Feline immunodeficiency virus

Feline immunodeficiency virus causes transplacental infection in cats and fetal death. About 60% of kittens can be nonviable. Fetal infection occurs as early as 3–4 weeks gestation, and the incidence of fetal infection increases with progressing gestation. Fetal resorptions and developmentally-arrested fetuses occurs early in gestation. Abortion is accompanied by abnormal inflammatory cytokine expression and Tregs play an essential role by suppressing inflammation. Placental inflammation may compromise pregnancy.


Coats KS. The feline immunodeficiency virus-infected cat: a model for lentivirus-induced placental immunopathology and reproductive failure (mini-review). Am J Reprod Immunol. 2005; 54: 169-185.

Coats KS, Boudreaux CE, Clay BT, Lockett NN, Scott VL. Placental immunopathology in the FIV-infected cat: a role for inflammation in compromised pregnancy? Vet Immunol Immunopathol. 2010; 134: 39-47.

Decaro N, Carmichael LE, Buonavoglia C. Viral reproductive pathogens of dogs and cats. Vet Clin North Am Small Anim Pract. 2012; 42: 583-598.

Feline infectious peritonitis virus

Phylum Pisuviricota, Class Pisoniviricetes, Order Nidovirales, Family Coronaviridae, Genus Tegacovirus, Species Alphacoronavirus 1


Decaro N, Carmichael LE, Buonavoglia C. Viral reproductive pathogens of dogs and cats. Vet Clin North Am Small Anim Pract. 2012; 42: 583-598.

Feline leukemia virus

Phylum Artverviricota, Class Revtraviricetes, Order Ortervirales, Family Retroviridae, Genus Gammaretrovirus, Species Feline leukemia virus

FeLV is recognised as a cause of embryonic mortality, abortion and perinatal mortality.

Powers JA, Chiu ES, Kraberger SJ, Roelke-Parker M, Lowery I, Erbeck K, Troyer R, Carver S, VandeWoude S. Feline Leukemia Virus (FeLV) Disease Outcomes in a Domestic Cat Breeding Colony: Relationship to Endogenous FeLV and Other Chronic Viral Infections. J Virol. 2018; 92:e00649-18.

Decaro N, Carmichael LE, Buonavoglia C. Viral reproductive pathogens of dogs and cats. Vet Clin North Am Small Anim Pract. 2012; 42: 583-598.

Feline panleukopenia virus (Feline parvovirus)

Phylum Cossaviricota, Class Quintoviricetes, Order Piccovirales Family Parvoviridae, Genus Protoparvovirus, Species Carnivore protoparvovirus 1, Feline parvovirus (FPV)

Feline parvovirus is a recognised cause of abortion in cats.


Decaro N, Carmichael LE, Buonavoglia C. Viral reproductive pathogens of dogs and cats. Vet Clin North Am Small Anim Pract. 2012 May;42(3):583-98, vii. doi: 10.1016/j.cvsm.2012.01.006. Epub 2012 Mar 3. PMID: 22482820; PMCID: PMC7114855.

Truyen U, Addie D, Belák S, Boucraut-Baralon C, Egberink H, Frymus T, Gruffydd-Jones T, Hartmann K, Hosie MJ, Lloret A, Lutz H, Marsilio F, Pennisi MG, Radford AD, Thiry E, Horzinek MC. Feline panleukopenia. ABCD guidelines on prevention and management. J Feline Med Surg. 2009; 11: 538-546.





Toxoplasma gondii

Phylum Apicomplexa, Class Conoidasida, Order Eucoccidiorida, Family Sarcocystidae, Genus Toxoplasma, Species Toxoplasma gondii


Toxoplasma gondii is a potential cause of failure of pregnancy. Dubey et al (1996) found that after experimental infection of 5 pregnant queens, 3 of 25 kittens were born dead. 4 kittens were eaten by their mothers. The placentas in 2 cases had multifocal necrosis and mineralisation that was especially visible from the allantoic surface of the chorioallantois.

Dubey JP, Mattix ME, Lipscomb TP. Lesions of neonatally induced toxoplasmosis in cats. Vet Pathol. 1996; 33: 290-295.