- 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