The benefits of a pregnancy ultrasound include:

• Confirms pregnancy so there is no question about false pregnancy and subsequent overfeeding of a bitch that 'appears' pregnant but is not
• Gives us an idea about litter size so we can manage the bitch's diet appropriately - bitches with large litter have very different caloric needs compared to bitches with small litters.  Overfeeding and underfeeding the bitch can result in overfeeding or underfeeding the fetuses. This can result in whelping problems (pups too big to be delivered easily, uterine inertia, inadequate pelvic size due to excess vaginal fat; or health problems in the puppies from being starved or overfed in utero)
• Lets us assess whether there are any resorbing fetuses and helps us deal with any inflammation we might diagnose at mid pregnancy thus preventing further fetal loss during pregnancy.
• Lets us pick up mucometra and hydrometra (2 common pathologic conditions) early and deal with them before they turn into pyometra.