Perinatal Mortality in Kittens: Causes, Risk Factors and Prevention

Perinatal mortality remains a significant challenge in feline neonatal care. Kittens are highly dependent on the queen during the first weeks of life, and physiological systems mature progressively after birth. Losses may occur as stillbirths during parturition or as neonatal deaths before weaning, with the highest vulnerability occurring during the first few days of life. 

Reported stillbirth rates range from 5% to 12.5%. Post-kittening mortality is particularly concentrated in the first week, with 91% of losses occurring during the first 3 days. Mortality between birth and weaning has been reported at approximately 8–14%.Recognising the factors associated with these losses allows veterinarians to focus monitoring and intervention where they are most needed^1,2,3,4. 

When Are Kittens Most at Risk? 

The immediate postnatal period is critical. Most post-kittening deaths occur during the first week, and approximately 13% of litters are affected by this phenomenon. An average mortality rate of 27% has also been reported⁴. 

The causes are frequently multifactorial, and the aetiology remains unidentified in approximately one-third of perinatal losses⁴. Therefore, assessment should extend beyond the kitten itself to include the queen, litter, parturition, and environment. 

Major Causes of Perinatal Loss⁴ 

Potential causes include: 

• Intrapartum or postnatal trauma 

• Infectious disease 

• Congenital defects and genetic disease 

• Low birth weight 

• Maternal factors 

• Environmental and management factors 

Infectious causes vary according to the management setting. Viral agents associated with stillbirth or neonatal death include feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), feline coronavirus (FCoV), feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), and feline pan-leukopenia virus (FPV)⁵. FHV-1 and FCV may also cause neonatal infections⁴. 

Bacterial infection is particularly important during the first week of life, commonly through septicaemia. Pathogens may include Staphylococcus species, Streptococcus species, Escherichia coli, Campylobacter species, and Salmonella species. Rare neonatal causes include Toxoplasma gondii and Neospora caninum. In shelter environments, severe flea infestation and coccidiosis may contribute to severe anaemia and death⁶. 

Maternal, Parturition, and Litter-Related Risks⁴ 

Queen-related factors can influence outcomes. Queens younger than 1 year have been associated with higher kitten mortality, while stillbirths have been associated with increasing queen age, particularly beyond 5 years. Breed differences have also been reported, with Persian, Manx and Himalayan cats described as predisposed to kitten losses. 

Larger litters have been associated with stillbirth and neonatal mortality. Dystocia is another important consideration. Although most queens deliver spontaneously, dystocia occurs in approximately 3–6% of cases. In a report involving 35 queens with dystocia, 69% of cases were attributed to maternal factors and 31% to fetal factors. 

Caesarean section may also be associated with postpartum kitten mortality and stillbirths. 

Environmental and Maternal Care⁴ 

Appropriate temperature, humidity, ventilation and hygiene are essential for neonatal survival. Queens and their litters should be separated from other cats to reduce infectious exposure and minimise maternal behavioural disturbances. 

Maternal illness, inadequate nutrition, stress, trauma, toxin ingestion and certain drugs can contribute to stillbirth or compromise neonatal survival. Maternal behavioural problems are also important. Poor care, rejection, or infanticide may result in trauma, haemorrhage, skin lesions or skeletal fractures. 

Hypothermia, hypoglycaemia and dehydration can further threaten neonatal survival, particularly when associated with illness, maternal neglect or prolonged fasting. 

Practical Clinical Insights 

For veterinarians managing a queen and litter, the first days after parturition warrant particularly close observation. Risk assessment should include: 

• Queen age, breed, health and maternal behaviour 

• Gestation and parturition history 

• Litter size and individual birth weights 

• Evidence of trauma or congenital abnormalities 

• Ability of each kitten to nurse 

• Environmental temperature, hygiene and separation from other cats 

• Signs suggesting infection, hypothermia, hypoglycaemia or dehydration 

Because perinatal loss is often multifactorial, identifying a single abnormality should not prevent assessment of the remaining risk factors. Early recognition of vulnerable kittens and prompt correction of preventable environmental, nutritional and maternal problems can form an important part of neonatal care. 

References 

1. Sparkes AH, Rogers K, Henley WE, Gunn-Moore DA, May JM, Gruffydd-Jones TJ, Bessant C. A questionnaire-based study of gestation, parturition and neonatal mortality in pedigree breeding cats in the UK. Journal of feline medicine and surgery. 2006 Jun;8(3):145-57. https://journals.sagepub.com/doi/pdf/10.1016/j.jfms.2005.10.003 

2. Fournier A, Masson M, Corbiere 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. Reproduction in Domestic Animals. 2017 Apr;52:153-7. https://onlinelibrary.wiley.com/doi/pdf/10.1111/rda.12844 

3. Romagnoli S, Bensaia C, Ferré-Dolcet L, Sontas HB, Stelletta C. Fertility parameters and reproductive management of Norwegian Forest Cats, Maine Coon, Persian and Bengal cats raised in Italy: a questionnaire-based study. Journal of Feline Medicine and Surgery. 2019 Dec;21(12):1188-97. https://journals.sagepub.com/doi/pdf/10.1177/1098612X18824181 

4. Veronesi MC, Fusi J. Feline neonatology: From birth to commencement of weaning–what to know for successful management. Journal of feline medicine and surgery. 2022 Mar;24(3):232-42. https://journals.sagepub.com/doi/full/10.1177/1098612X221079709 

5. Evermann JF, Kennedy MA. Viral infections. Small animal pediatrics. 2010 Sep 2:119. https://pmc.ncbi.nlm.nih.gov/articles/PMC7152367/pdf/main.pdf 

6. Lamm CG, Njaa BL. Clinical approach to abortion, stillbirth, and neonatal death in dogs and cats. Veterinary Clinics: Small Animal Practice. 2012 May 1;42(3):501-13. https://www.vetsmall.theclinics.com/article/S0195-5616(12)00016-2/pdf