Dog Miscarriage: Puppy Loss During Dog Pregnancy

Last updated: Sept 24, 2020

What goes on in the uterus can seem very mysterious during a canine pregnancy. There is no window in there to assess what is going on; what number of puppies there are, how they are developing, or what sex and color they are.

There are many things that can go wrong during a developing pregnancy. Up to 30 percent of conceived pups have been estimated to be lost during this time.

Prior to day 28 (or slightly earlier, depending on the veterinary ultrasound equipment and operator) we cannot assess for pregnancy. If she is not pregnant, we have no way to know if there was a failure to conceive pups or a failure to carry the pups to this point. After day 28, the time at which we can assess for pregnancy on ultrasound, we can begin to understand fetal loss. This is why an abdominal ultrasound during mid-pregnancy is so important. For the next time, we will do a different set of diagnostics or a different breeding plan if she was pregnant and the pregnancy failed than if she failed to conceive.

Fetuses lost before day 45 of pregnancy are usually resorbed. This means the pups started to develop, then failed to grow and develop. Because this is prior to day 45, the skeletons are not calcified, allowing the resorption. Resorption means the pups stop developing, and the placenta and pups quietly slip away. In most cases, you will not see any vaginal discharge or signs of labor. Sometimes, there is evidence of a lost fetus because of the character of the placenta and associated debris on a neighboring puppy at vaginal delivery. If a c-section is performed, thickened areas of the uterus can be felt. There is a yellow to gray thick mucusy pocket of fluid. If cultured, it usually does not grow bacteria. This should NOT be confused with a pyometra or infection in the uterus. The female should NOT be spayed. However, a biopsy of this area can be collected at c-section and submitted for diagnostics. In some cases, the cause of the resorption can be determined by a pathologist doing a microscopic evaluation of the placenta, placental site, and uterus. This is the ideal time to collect this information, to help determine how to best manage her next attempt at a pregnancy.

Pups lost after day 45 of pregnancy do not resorb. They stop developing and can be seen at delivery as calcified but tiny puppies with skeletons and various bits and parts of a puppy. It is clear that they were not meant to survive. Pups lost very close to the time of delivery may be normal or almost normal sized at birth, but with skin layers peeling off their faces. Again, once this is seen, it is clear you cannot save these pups.

If you have more questions on dog pregnancy, call a Revival Pet Care Pro at 800.786.4751.

-Dr. Greer
Marty Greer, Doctor of Veterinary Medicine, Director of Veterinary Services at Revival Animal Health

Marty Greer, Doctor of Veterinary Medicine, has 35+ years' experience in veterinary medicine, with special interests in canine reproduction and pediatrics. She received her Doctor of Veterinary Medicine from Iowa State University in 1981. She's served as Revival's Director of Veterinary Services since 2019.