A retained placenta is a very serious and life-threatening condition for a cat as a retained and unremoved placenta will begin to decompose within the cat’s uterus, causing a dangerous bacterial infection that will likely spread to the cat’s bloodstream and throughout the body. A cat that has been unable to pass a placenta must be treated by a veterinarian immediately.

As the fetuses develop within the uterus of the mother cat, often called a queen, each fetus is surrounded by an individual membranous sack that also contains the placenta. During a normal birthing process, the kittens usually emerge from the birth canal while still attached to the placenta, which the queen will remove and often eat instinctively. On occasion, however, kittens will be born without the placenta, which will pass through the birth canal after the kitten is born. If the kitten is not born with its placenta and the placenta does not follow soon after a kitten born without it, the placenta has been retained within the uterus.

There are many signs that can alert a pet owner to a retained placenta. The first, yet least reliable, clue is that the number of kittens that have been born and the number of placentas that have been passed do not match. This can be unreliable because it is not uncommon for a mother cat to eat one or more of the placentas. It is believed that cats do this instinctively to prevent smells that would attract predators. It is difficult to be certain regarding the number of placentas that have passed. Signs that should alert a pet owner to the possibility that a placenta may have been retained are as follows:

Retained placentas are rare in cats. When retained placentas do occur in a cat, they often follow an abnormally difficult labor, referred to as dystocia. Dystocia can result if the queen was not healthy when she went into labor, if one or more kittens are in positions that make them difficult to birth, if one or more kittens are abnormally large, if one or more kittens are stillborn and difficult to birth, and if the number of kittens in the litter is unusually large. Any of these factors can result in one or more placentas being retained inside the uterus.

If your cat has recently given birth and has begun to exhibit some or many of the signs listed above, it is imperative that you call your veterinarian or a veterinary emergency hospital immediately as your cat may be in grave danger. The following will likely occur when your cat is seen by the veterinarian. 

Upon diagnosing your cat with a retained placenta, your veterinarian may first choose to administer an injection of oxytocin to stimulate contractions of the uterus in order to facilitate the passing of the retained placenta. Your cat will also likely receive intravenous fluids to combat dehydration, which is a risk after any birth but especially after a difficult birth. If the oxytocin does not cause your cat to pass the retained placenta, it may be necessary for the veterinarian to perform a surgical procedure to remove the placenta from the uterus. Dependent upon how strong and widespread the infection is, it may be necessary for the veterinarian to spay your cat, or remove the ovaries and uterus, to prevent further infection. Even if the reproductive organs do not need to be removed for emergency medical reasons your veterinairan may encourage you to have your cat spayed during this procedure to prevent her from having to endure the possibility of another difficult and dangerous labor in the future. 

Your cat’s prognosis is largely dependent upon how quickly your cat received veterinary treatment after retaining a placenta and which treatment, whether medical or surgical, your cat required.  If you and your veterinarian discovered the retained placenta before it began to decompose and the placenta then passed after a dose of oxytocin, your cat will likely not have any additional recovery than that which is natural after giving birth. If your cat developed an infection before oxytocin was effective, your cat may be on antibiotics for several days and will likely be lethargic as she rests. A queen that has had a celiotomy will need several days to more than a week to heal from the surgery and may require antibiotics and pain medication. Your veterinarian will advise you as to whether it is safe for the mother to nurse the kittens while she is on medication or if you will need to feed the kittens with a milk replacement that can often be purchased through your veterinarian’s office or at a pet store. The queen and her kittens will likely need to be re-examined by the veterinarian in the days or weeks following to ensure that your cat has healed and that the infection has subsided.