Uterine Inertia

Introduction

Uterine inertia describes the failure of the uterus to expel a foetus normally and is a common cause of canine and feline dystocia.

Uterine inertia can be primary or secondary.

Primary Uterine Inertia

This describes the total or partial absence of contractions to expel a normal foetus through an unobstructed birth canal.

Several causes have been found:

Breed predisposition

Large litter overstretching the uterus

Small litter not stimulating the uterus enough. Small foetuses cannot apply enough pressure on the uterine wall and cervix to set up the Fergusson reflex.

Systemic disease: Obesity and lack of exercise, hypocalcaemia, septicaemia.

Complete primary uterine inertia occurs if 2nd stage labour does not begin. Partial inertia occurs if the 2nd stage begins but contractions soon fail.

Secondary Uterine Inertia

Uterine muscles become exhausted after prolonged contraction against an obstructing or oversized foetus or during birth of a large litter. There is usually subclinical hypocalcaemia and/or hypoglycaemia.

This can occur in the sow, bitch and guinea pig.

See also: Dystocia in the Dog and Cat

Uterine Inertia Learning Resources
Flashcards Test your knowledge using flashcard type questions	Small Animal Soft Tissue Surgery Q&A 12

References

Pasquini, C. (1999) Tschauner's Guide to Small Animal Clinics Sudz Publishing

Slatter, D. (2002) Textbook of small animal surgery Elsevier Health Sciences

Noakes, D. (2001) Arthur's Veterinary Reproduction and Obstetrics Elsevier Health Sciences