Introduction

• Pregnancy loss in the queen may be associated with embryo resorption if occurs during the first half of pregnancy or abortion of fetuses during the second half of pregnancy.
• Resorption of embryos and abortion may occur during the same gestation.
• Embryo resorption can be clinically diagnosed by serial ultrasonography as the failure of one or more embryonic vesicles to show normal embryonic and fetal development according to the gestational age. The affected embryonic vesicles get progressively smaller and embryo/fetuses, whenever present, are asystolic. In resorption alone, there is no vulvar discharge.
• Abortion is fetal death and expelling of some or all of the uterine contents in a vulvar discharge.
• Cause: maternal trauma and miscellaneous disease primarily affecting the queen, fetal abnormalities, and specific infections such as feline leukemia virus and chlamydia. Nutritional insufficiency has been reported to cause pregnancy loss in the queen.
• Diagnosis: history, clinical examination and laboratory tests.
• Treatment: depends on cause.
• Prognosis: depends on cause.

Pathogenesis

Etiology

• Maternal distress.
• Uterine damage.
• Drugs:
  • Drugs causing teratogenic effects.
  • Drugs directly affecting the uterus.
• Fetal genetic (chromosomal) abnormalities, particularly owing to inbreeding. In Manx cats, inbreeding may lead to a syndrome associated with the tailless condition likely caused by an autosomal dominant factor, often accompanied by other abnormalities such as spina bifida Spina bifida, urinary and fecal incontinence Urinary incontinence, and disturbances in gait caused by abnormal anatomy of pelvic limbs.
• Infections:
  • Feline leukemia virus (FeLV) Feline leukemia virus.
  • Feline panleukopenia virus  Feline panleucopenia virus disease.
  • Feline immunodeficiency virus Feline immunodeficiency virus.
  • Chlamydophila abortus Chlamydia disease.

Predisposing factors

General

• Queens from impoverished backgrounds are probably at an increased risk of aborting as they are more likely to be involved in accidents, have major infections and to be on a poor diet.

• Cats in breeding catteries are probably at an increased risk of certain infections compared to individual pet cats: FIP Feline infectious peritonitis, respiratory viruses Viral-induced upper respiratory tract disease, Chlamydophila abortus.
• Genetic: inbreeding may lead to fetal abnormalities and fetal losses.

Diagnosis

Treatment

Prevention

Outcomes