Uterine Inertia

• Protracted birth due to weak or absent uterine contractions.

Primary Uterine Inertia

• Lack of Oxytocin Receptors
• Lack or failure of Oxytocin release
• Lack or failure in Prostaglandin release
• Obesity and lack of excercise in bitches. The small foetus cannot apply enough pressure on the uterine wall and cervix to set up the Fergusson reflex.
• Foetus is too small, or not entering cervix.

Secondary Uterine Inertia

• Dystocia with subsequent muscle failure
• Large number or size of offspring causes the uterine muscle to become stretched and fatigued.
• Common in sow, bitch and guinea pig