Miscarriage, Abortion, Loss of Pregnancy in Cats and Dogs

Updated: Sep 19, 2021

What is miscarriage in cats and dogs?


Clinically, miscarriage is pregnancy loss

What is abortion?


Abortion is well-defined as the eviction of foetuses before full-term pregnancy, i.e., before the fertilised egg is capable of independent life. Abortion is unusual in the bitch. However, foetal reabsorption or mummification is more common.

What is foetal reabsorption?


It is also referred to as canine foetal resorption. It is a biochemical process whereby a puppy within the womb is absorbed. The tissues of a live foetal organism, the puppy, deteriorate and decompose completely through a process of disintegration of the enzymes in the foetus inside the womb allowing for complete destruction of the organism resulting in total reabsorption. Puppy absorption cannot happen after a certain amount of days (44 days roughly) because of the development of the skeletal bones, those of which cannot be reabsorbed. Therefore, canine reabsorption only occurs during the earlier stages of pregnancy when the foetus is made up of mostly soft tissues.

What is foetal mummification?

Foetal mummification refers to the death of foetuses after the calcification of the skeleton, around day 50 of the pregnancy in the dog. It often leads to the mummification of foetuses. The foetuses are retained within the uterus, and degradation happens to a certain extent, leaving the skin dry around the foetus, forming a membrane that may hinder full foetal decay and reabsorption for prolonged periods. Mummified foetuses are generally retained in non-infected uteri, and the general health of the dam is usually not affected. The skull and skeletal parts are also intact, and the foetus remains more or less distinguishable in the uterus by ultrasound and x-ray. Diseases of the uterus often lead to complete foetal dissolution and decomposition and may affect the dam’s health.

What are the differences between stillbirth and neonatal death?


A newborn puppy (neonate) born dead at full term is called a stillborn. Neonatal (newborn) death is judged to be loss of life within the first 3 weeks after the birth of the puppy.

What are the causes of abortion in cats and dogs?


The causes of abortion in cats and dogs are either infectious or non-infectious.

Infectious causes:

These can be broadly grouped into Viral, Bacterial, Fungal, and Protozoal diseases.

1. Viral causes


Common viral diseases causing abortions and neonatal deaths in dogs include:-

i). Herpesviral infection (most common cause)

ii). Bluetongue virus (BTV)

iii). Canine parvovirus-1 (canine minute virus),

iv). Canine distemper virus (CDV), and

v). Canine adenovirus-1 (CAV1).

Usually, foetal and neonatal deaths may possibly be secondary to maternal illness or due to direct infection.

Viral diseases causing abortions and neonatal deaths in cats include:-

i). Feline leukaemia virus,

ii). Feline parvovirus (feline panleukopenia virus),

iii). Feline immunodeficiency virus (FIV),

iv). Feline coronavirus, and

v). Feline calicivirus (FCaV).

2. Bacterial causes