Hi there, Leanne here again from ScanX, we’ve previously spoken about different ultrasound transducers, modes and given you a comprehensive guide to ultrasound. Now it’s time to use the machines, so it’s now time to learn about what we might find, and when to seek veterinarian assistance.

In this blog, we will be looking at singleton pups. You might be wondering what relevance this has to you: why is singleton detection so important? How will ultrasound help?

Singleton pups: overview

A singleton puppy is where only one puppy develops in the uterus; a fairly rare occurrence more commonly found in smaller breeds who tend to have a smaller litter. The cause of a singleton pup isn’t widely known.

You might be thinking “what is the issue? Surely one puppy is easier for the mother to carry, deliver and care for?” Unfortunately, this is often not the case. For example, the average litter size for a cocker spaniel is between 3-7 pups, their growth develops proportionally to shared nutrients and space in utero and means they are ideally sized to fit through the birth canal without intervention. If only one puppy is present, they are more than likely to be bigger than the ideal, and cause complications during birth and afterwards during development.

Ultrasound is very safe & effective of confirming pregnancy, especially when using a machine such as ScanX. If a singleton puppy is found at the first scan (30 days post mating), subsequent scans can track the pup’s development, allowing you to consult with your veterinarian to create the best treatment plan for your pets.

Birthing complications: fetal dystocia             

Parturition (giving birth) relies on a decrease in progesterone 24-48 prior to onset of labor, before an increase in oxytocin. The rise in oxytocin is what stimulate uterine contractions, but often singleton pups can’t produce the levels of oxytocin needed to stimulate uterine contractions to allow passage into the birth canal.

This could be why in some cases where ultrasound hasn’t been used during pregnancy, fetal dystocia may only be noted during parturition. If left unassisted, the birth will be problematic for both the dam & pup (with fetal distress and possibly death).

Many singleton` pups will require a cesarian section. If ultrasound has been performed throughout the pregnancy, many owners will arrange cesarian sections with their veterinarian to ensure viability of the pup and the dams safety.

Singleton puppies after birth: development

Due to development in isolation without siblings, singleton pups will not intuitively learn habits such as bite inhibition and other social skills. These puppies often display inability to handle frustration, and touch sensitivity has also been observed. However, with good socialization with other dogs, these issues are easily overcome and a singleton pup should not experience any long-term health problems.

As a result of having no litter mates, singletons may need extra heat sources, as well as stimulation to imitate a normal litter and to encourage movement and exercise. The mother could also struggle post parturition with milk becoming over produced or under produced. With an over production of milk, you must check the mother for any signs of mastitis; if the dam cannot produce enough milk, it would be necessary to begin supplementing feeding or look to completely hand rearing the puppy.


While it is not possible to prevent a singleton pregnancy, the early detection of singletons and monitoring them throughout pregnancy is important. No other imaging modality can do this as early, cost-effectively and safely as ultrasound.

Detecting a singleton pup early means that plans can be developed early to ensure the wellbeing of the mother and  her pup.