Introduction
Certain dog breeds are unable to give birth naturally due to their physical characteristics. This is an important topic for dog owners and breeders to understand, as it impacts the health and wellbeing of both mother and puppies. Dogs that cannot whelp naturally require caesarean sections in order to give birth safely. Being aware of dog breeds predisposed to obstructed labor empowers owners to make informed breeding and veterinary decisions.
Physical Reasons
Certain dog breeds physically cannot give birth naturally due to the size and shape of their skulls and pelvis. Brachycephalic (short-nosed) breeds like English Bulldogs, French Bulldogs, Boston Terriers, and Pugs tend to have disproportionately large heads and narrow pelvises compared to their body size. This is due to selective breeding to exaggerate desired physical traits over many generations.
According to research comparing dog skull and pelvis sizes across breeds, “In general, greyhounds have a significantly larger pelvis than do pit bulls. The pelvic shapes of these two breeds also resemble, to some extent, the trade-off between thermoregulation and locomotion vs. offspring gestation and parturition.”[1] Brachycephalic breeds fall on the extreme end of this trade-off, with skull and pelvis sizes that make vaginal birth nearly impossible.
The large head size of brachycephalic puppies simply cannot physically pass through the narrow birth canal. This can put both the puppies and mother at risk during attempted vaginal birth. Cesarean sections are almost always required for safe delivery of brachycephalic litters.
[1] Genetics of canid skeletal variation: Size and shape of the dog pelvis. National Library of Medicine.
English Bulldog
The English Bulldog breed originated in England in the 16th century for the purpose of bull baiting. They were bred to have a large head, wide shoulders, and sturdy, compact body. These physical traits make it difficult for English Bulldogs to mate and give birth naturally.
According to a study published in Theriogenology, the rate of caesarian section for English Bulldogs is over 80% (Evans, 2010). Their large head size, pushed-in face, and narrow hips make vaginal delivery challenging if not impossible. The puppies’ heads are often too large to pass through the mother’s pelvis.
Due to these extreme physical traits, most English Bulldog births require scheduled caesarian sections to avoid complications and ensure the health of the mother and puppies. The high rate of caesarian sections for English Bulldogs is a consequence of selective breeding for exaggerated features over many generations.
French Bulldog
The French Bulldog originated in England and was created to be a miniature version of the Bulldog. They were brought to France in the late 1800s and became extremely popular, leading to their “French” moniker. Selective breeding led to the bat-like ears and compact, muscular body of the French Bulldog we know today (proportion of litters of purebred dogs born by caesarean section).
Unfortunately, the characteristic smashed-face and large head of the French Bulldog make natural birthing physically impossible for the vast majority. Their hips are too narrow, heads too big, and the puppies cannot fit through the birth canal. This is known as an obstructed labor. As a result, around 80-85% of French Bulldog litters are delivered by c-section (Study: French Bulldogs More Likely to Suffer from Difficult Births).
Boston Terrier
The Boston terrier originated around 1870 in Boston, Massachusetts as a cross between an English bulldog and an English white terrier. Selective breeding over the years has produced a small companion breed with a short, squat, muscular build and a short, broad head featuring a short muzzle, wide set eyes, and erect ears. Their coat is fine, smooth, and short (University of Edinburgh, 2015).
One of the defining characteristics of the Boston terrier is a brachycephalic (shortened) skull and muzzle. Unfortunately, this physical trait makes giving birth naturally very difficult. As early as the 1930s, studies showed Boston terriers had a high rate of caesarean sections, and more recent research indicates 92% of Boston terrier pregnancies result in c-sections, primarily due to their head shape causing dystocia (inability to give birth naturally) (Evans et al., 2010; UFAW, n.d.).
While individual dogs may occasionally give birth naturally, the Boston terrier breed has such a high rate of needing caesarean sections that this method of delivery is considered the norm. Breeders and veterinarians routinely schedule c-sections for Boston terriers rather than waiting until the mother shows signs of difficulty whelping. This allows the procedure to be performed safely in controlled conditions.
Pug
The Pug is an ancient breed that can be traced back over 2,000 years to ancient China. They were bred to be companion dogs and prized by Chinese emperors. Pugs have very distinct physical characteristics with their square, compact bodies, deep wrinkles on their foreheads and muzzles, large round eyes and curly tails.
One of the main reasons Pugs often require caesarean sections is due to their large heads and narrow hips. Pug puppies have disproportionately large heads compared to the mother’s small pelvis, making natural delivery extremely difficult if not impossible. On average, over 80% of Pug litters are delivered by c-section.
Additional issues contributing to difficult births in Pugs include their short muzzles, which can obstruct breathing during delivery, and flat faces which do not allow puppies to align properly in the birth canal. Their curly tails can also prevent normal positioning. Due to these physical traits, veterinarians strongly recommend caesarean sections for Pug mothers to reduce risks to both the puppies and mother.
Other Brachycephalic Breeds
Other brachycephalic dog breeds also have high rates of caesarean sections due to their physiology. According to a paper published on the NCBI website, “Especially brachycephalic breeds are known to have a high risk of cesarean sections” (Parameters in Canines After Cesarean Sections – PMC). Some other high risk breeds include Boxers, Shih Tzus, Chihuahuas, and Pekingese.
These breeds tend to have large heads and narrow hips, making natural birth difficult and dangerous. The compressed snouts of brachycephalic dogs also often leads to respiratory issues during the birthing process. For the safety of the mother and puppies, caesarean sections are commonly recommended for these high risk breeds.
Health Risks
A C-section is major abdominal surgery, so there are risks involved for both the mother dog and her puppies. For the mother dog, a C-section carries the normal risks associated with anesthesia and surgery, including bleeding, infection at the incision site, and complications during recovery like wound dehiscence (Potential Complications After Your Dog’s C-Section). The mother may also experience pain and discomfort during the recovery period.
There are also potential risks to the puppies during a C-section. If the puppies are significantly overdue, they may have grown too large to be easily delivered through the incision. Puppies can also experience respiratory issues if they are not stimulated to breathe fast enough after delivery. Premature puppies are at higher risk of health complications. Proper aftercare for the mother, including antibiotics and pain management, helps reduce these risks (Caesarean Sections in Dogs – Post-Operative Instructions | VCA).
Alternatives
Since some breeds like English Bulldogs, French Bulldogs, Boston Terriers, and Pugs cannot give birth naturally due to their narrow hips and large puppy head size, breeders have turned to alternatives like selective breeding, artificial insemination (AI), and Caesarean sections (C-sections) with a veterinarian.
Selective breeding involves choosing dogs with wider hips and smaller heads to breed together in hopes of producing puppies with a lower risk of birthing complications. However, this can take many generations and does not completely eliminate the risks.
Artificial insemination allows the female dog to become pregnant without natural breeding. This reduces chances of physical harm during mating. However, she will still likely require a C-section for delivery.
Performing an elective C-section with a veterinarian when the female dog is full term is currently the safest option. The surgery is done under anesthesia and allows the vet to safely remove the puppies one by one. While a major surgery, it greatly reduces health risks to both the mother and puppies during the birth process.
Conclusion
In summary, certain breeds of dogs like English Bulldogs, French Bulldogs, Boston Terriers, and Pugs cannot give birth naturally due to their small pelvises and large head sizes. This is a result of selective breeding to exaggerate certain physical traits. While cesarean sections allow these breeds to reproduce, the procedure is not without health risks to the mother and puppies. Responsible breeding practices can help mitigate some of these risks. However, breeding dogs purely for profit without considering their health and wellbeing raises important ethical questions that deserve further discussion. As we learn more about canine genetics and the long-term impacts of selective breeding, the future of ethical breeding remains unclear. There is still much progress to be made in changing breed standards and breeding practices to prioritize health over appearance.