Overall, there is some evidence to suggest that the mortality rates of newborn puppies can be reduced if pregnant bitches are scheduled for elective caesareans compared to undergoing an emergency caesarean where complications are more likely to develop. It is, however, critical to recognise that potential bias in retrospective studies can be significant and the papers reviewed did not consider impact on the bitch or long-term survival of disease risks of puppies born by caesarean section.
Imagine this clinical scenario: a client has brought their pregnant French Bulldog who is a few days from her due date to your first opinion veterinary practice. Following a radiographic examination, you have concerns regarding the risk of dystocia due to foetopelvic disproportion, alongside other complications associated with brachycephalic breeds, which could endanger the lives of the mother and her puppies. The client has strong beliefs in natural vaginal deliveries of newborns with the use of homeopathic or herbal remedies to facilitate labour and delivery if necessary. An emergency caesarean section may be necessary to resolve dystocia, which may increase surgical and anaesthetic risks and possibly result in puppy loss.
An emergency caesarean section may be necessary to resolve dystocia, which may increase surgical and anaesthetic risks and possibly result in puppy loss
You decide to explore whether the evidence supports the use of elective caesarean sections, particularly in situations or breeds with predispositions to dystocia, to maximise the survival of the puppies compared to vaginal delivery or emergency caesarean section.
The evidence
Two retrospective studies were critically appraised.
Proctor-Brown et al. (2019) studied 836 puppies from 53 different breeds, most commonly the English/American Bulldog and Labrador Retriever. There were 150 bitches who underwent caesarean sections in the study, 104 of which were emergency and 46 were elective cases. Of those that underwent caesarean, 40 percent (59/150) of the bitches were brachycephalic breeds, of which 39 percent (23/59) underwent elective caesareans. The percentage of neonatal death from emergency compared to elective caesarean sections decreased from 43 percent (45/104) to 15 percent (7/46). Only 38 percent (6/16) of vaginal deliveries in emergency cases were successful. There was also an odds ratio of 6.67 for a minimum of one deceased puppy delivered via caesarean section should the anaesthetic time increase over 120 minutes.
Natural delivery of puppies can lead to a 20 percent risk of perinatal mortality, which could be reduced to 2 percent with elective caesarean section
In a 2019 study by Alonge and Melandri, 46 Great Dane litters were studied, including a total of 303 puppies. The number of stillbirths and neonatal mortalities had a statistically significant reduction in elective c-sections in comparison to vaginal deliveries and emergency c-sections. Neonatal mortalities were as follows: 2 percent in elective caesarean section, 10 percent in emergency caesarean section and 19 percent in vaginal delivery. The study’s authors suggested that dystocia and prolonged labour were some of the main factors resulting in neonatal death. Natural delivery of puppies can lead to a 20 percent risk of perinatal mortality, which could be reduced to 2 percent with elective caesarean section. Limitations of this study include the fact that only one breed of dog was studied and that the breed is not predisposed to dystocia. The authors discussed other factors to consider surrounding c-sections, including indications for the best time to perform surgery, anaesthetic protocol and diet of the pregnant bitch.
Conclusion
Overall, there is some evidence to suggest that the mortality rates of newborn puppies can be reduced if pregnant bitches are scheduled for elective caesareans compared to undergoing an emergency caesarean when complications develop, particularly in breeds with higher risks of dystocia. However, only two studies were critically appraised and both were retrospective studies, so are associated with limitations such as selection bias and the inability to control variables.
It is also important to recognise that an elective caesarean section should not be considered as a first-line intervention due to associated anaesthetic and surgical risks, and that the bitch may be able to whelp the puppies with only assistance, not surgical interventions. It has been suggested that puppies may benefit from a vaginal delivery rather than a caesarean section due to greater vitality (Oliva et al., 2018). Mortality or survival statistics of puppies in existing literature alone should not solely determine if a patient should be scheduled for elective caesarean sections. Anaesthetic protocols and other factors such as the size of the litter, the breed and the age of the pregnant bitch should also be considered (Cornelius et al., 2019).
It is also important to recognise that an elective caesarean section should not be considered as a first-line intervention due to associated anaesthetic and surgical risks
There is also currently still resistance, from both breeders and first opinion veterinary practices, to perform routine elective caesarean sections. There is an argument that by offering elective c-sections, veterinary practices are supporting the breeding of canine breeds predisposed to dystocia and that are not capable of reproducing naturally without veterinary assistance. Further ethical considerations, such as whether there is a higher risk of the bitch experiencing more pain and complications with surgical delivery, should be considered in future prospective studies.
Future studies could investigate the detection of labour, symptoms of dystocia and timing of decisions made regarding surgery.
The full Knowledge Summary can be read in RCVS Knowledge’s open access journal Veterinary Evidence.
