Dystocia is defined as a difficult birthing experience. This can be due to abnormalities attributed to the bitch, the puppies or both. Dystocia is a common problem in dogs; it is thought to occur in approximately 5% of bitches but certain breeds have a close to 100% dystocia rate.
A number of factors can contribute to dystocia in dogs:
- Large litter size
- Poor nutrition of the dam during pregnancy
- Breed conformation (e.g. brachycephalic dogs have wide broad foreheads and flat faces making delivery through the birthing canal difficult)
- Small pelvic canal in the dam
- Age of the dam (very young or very old)
- Small breeds predisposed to eclampsia
Induction of Parturition
There are three stages of labour;
- The 1st stage: the start of uterine contractions, relaxation of the cervix and rupturing of the membranes (i.e. water breaking)
- The 2nd stage: foetuses are delivered by uterine contractions. From the time that the first foetus is born, the second stage of labour should take no more than four hours. The time between foetuses is generally between 20-60 minutes
- The 3rd stage: the delivery of the foetal membranes
Dystocia occurs in second stage labour where there is a difficulty delivering the foetuses. This may be attributable to the dam or the foetus.
The foetal causes of dystocia can be due to abnormal presentation or positioning (e.g. breech position), oversized foetuses, birth defects and foetal death. These abnormalities usually result in the foetus becoming obstructed in the birthing canal.
The more common causes attributable to the bitch include poor uterine contractions, narrow or abnormal pelvic canal, uterine torsion (i.e. uterine twist) and uterine rupture (i.e. uterine tear). Inadequate contractions of the uterus (i.e. uterine inertia) is the most common cause of dystocia in dogs. The poor uterine contractions can be due to inappropriate stimulation of labour, or fatigue. Labour normally begins as a result of signals initiated by the puppies. Where there are only one or two puppies, there may be inefficient initiation of labour and therefore inefficient contractions in second stage labour. Lack of uterine contractions can also be due to exhaustion or eclampsia in the bitch.
Signs of Dystocia
- The rectal temperature has dropped and returned to normal with no sign of labour.
- Green vulvar discharge with no foetuses delivered. This discharge suggests the placenta has separated from the uterine lining and indicates a need for immediate intervention.
- Foul smelling discharge. This usually suggests that one or more of the foetuses have died.
- Delivery of stillborn puppies.
- Passing of foetal fluids 2-3 hours beforehand and no signs of labour.
- Strong and persistent abdominal contractions by the dam for more than 20-30 minutes with no delivery of a foetus.
- A puppy in the pelvic canal without abdominal contractions from the bitch or movement of the puppy.
- An unwell bitch (e.g. agitated, vomiting, trembling).
- Persistent nesting behaviour (e.g. digging, circling).
If any of these signs occur, the bitch and puppies require veterinary attention immediately.
Dogs that are in distress and that have shown any of the above signs require veterinary attention and in some cases hospitalisation. The bitch may be suffering from low blood calcium, low blood sugar, or inadequate oxytocin hormone. Medications to promote uterine contractions may be used to assist labour, but will not be administered if an obstructive dystocia is suspected as it can lead to foetal death.
The veterinarian may try to reposition a foetus obstructed in the birthing canal by digital manipulation or using instruments. This can help promote a normal delivery of the foetus.
Where this is not successful or foetal stress is detected on examination, your veterinarian may recommend delivery of the foetuses by caesarean section.
Any bitch intended for breeding should have a veterinary examination prior to taking part in a breeding program. A thorough pre-breeding examination can help identify any anatomical abnormalities that may prevent the bitch carrying the litter to term or interfere with the delivery of the puppies.
Veterinary examination of the bitch during pregnancy is critical to ensure body weight is optimal, the puppies are developing normally and provides information as to how many puppies the bitch is carrying. Knowledge of the exact litter size can provide clues for detecting dystocia (e.g. when six puppies are expected and only five are delivered, this requires immediate intervention).