A cat miscarriage typically involves abnormal vaginal discharge, visible distress, and sometimes the delivery of underdeveloped or stillborn kittens. What you actually see depends heavily on how far along the pregnancy is. Early losses can be nearly invisible, while later miscarriages look much more like a difficult labor with obvious physical evidence.
What You’ll See Physically
The most common visible sign is vaginal discharge that looks clearly abnormal. Rather than the slight, clear discharge that can be normal during pregnancy, miscarriage-related discharge is typically brown, green, black, or pus-colored. This discharge can appear at any point during the pregnancy, and its color often reflects the breakdown of placental or fetal tissue.
If the miscarriage happens in the later stages of pregnancy (roughly the second half, after about 4 weeks), your cat may go through contractions and deliver stillborn kittens. These may be visibly underdeveloped, partially formed, or encased in their amniotic sacs. You might also see expelled tissue that looks like dark, fleshy masses. In some cases, a cat delivers one or more stillborn kittens alongside living ones, losing only part of the litter.
Fever is another key sign. If your cat feels unusually warm and is showing discharge, the combination points strongly toward either miscarriage or uterine infection, both of which need veterinary attention.
Early Pregnancy Loss Can Be Invisible
Cats that lose a pregnancy very early, within the first few weeks, often show no outward signs at all. The body reabsorbs the tiny embryos in a process called fetal resorption. The tissue is broken down and absorbed back into the uterine lining without any discharge, contractions, or expelled material. From the outside, it simply looks like the cat was never pregnant.
This is actually the most common type of feline pregnancy loss. You might suspect it only if your cat was confirmed pregnant (through ultrasound or obvious belly growth) and then her abdomen seems to shrink, or she never progresses to delivering kittens. A cat can also resorb some embryos while continuing to carry others to term, meaning a smaller-than-expected litter at birth is sometimes the only clue that a partial loss occurred.
Behavioral Signs to Watch For
Beyond the physical evidence, a miscarrying cat typically shows signs of pain and general illness. Abdominal pain is common, and your cat may hunch her body, resist being picked up, or react when her belly is touched. She may become unusually lethargic, hiding more than usual and losing interest in food. Some cats excessively lick or groom their genital area in response to the discharge and discomfort.
Restlessness and vocalization can also occur, particularly if contractions are involved. This can look similar to the early stages of normal labor, which makes it confusing if you’re expecting kittens. The key differences are timing (contractions well before the expected delivery date, which is around 63 to 65 days after mating) and the presence of abnormally colored discharge rather than the clear fluid that precedes a healthy birth.
Common Causes of Feline Miscarriage
Infections are one of the leading causes. Feline herpesvirus is a well-documented trigger of pregnancy loss, and other infections including feline leukemia virus and feline panleukopenia virus can also cause miscarriage. Bacterial infections of the uterus are another frequent culprit, sometimes developing silently until the pregnancy fails.
Beyond infections, hormonal imbalances play a significant role. Cats need sustained levels of progesterone to maintain a pregnancy, and if those levels drop too early, the uterus can’t support the developing kittens. Physical trauma, severe stress, nutritional deficiencies, and genetic abnormalities in the fetuses can also lead to pregnancy loss. In many cases, especially with early resorption, the exact cause is never identified.
How a Vet Confirms Pregnancy Loss
Ultrasound is the primary tool for evaluating what’s happening. It can confirm whether fetuses are still viable by detecting heartbeats, and it can reveal whether any fetal or placental tissue remains in the uterus after a miscarriage. Ultrasound is most reliable for pregnancy detection between days 25 and 35 of gestation, but it’s useful throughout pregnancy for checking fetal health. It also helps distinguish between a miscarriage and other serious conditions like a uterine infection filled with pus, which can look similar from the outside.
Blood work may be run alongside imaging to check for signs of infection, inflammation, or hormonal problems. If an infectious cause is suspected, your vet may test for specific viruses.
What Happens After a Miscarriage
The biggest concern after a miscarriage is whether all fetal and placental tissue has been fully expelled. Retained tissue left inside the uterus creates a serious risk of infection, which can develop into a life-threatening uterine condition called pyometra, where the uterus fills with pus. Prolonged bloody or foul-smelling discharge after a miscarriage is a warning sign that tissue may still be present.
If retained tissue is found on ultrasound, treatment focuses on helping the uterus contract and expel it. In more severe cases, or when infection has already set in, surgical removal of the uterus (spaying) may be the safest option. For cats whose owners want to preserve breeding ability, medical management with drugs that stimulate uterine contractions is sometimes possible, though it requires close veterinary monitoring.
Even after a straightforward miscarriage where everything is expelled naturally, most vets recommend a follow-up exam to confirm the uterus has returned to normal and no infection is developing. Cats that have experienced one miscarriage are not necessarily at higher risk for future losses, but identifying and treating the underlying cause, whether it’s an infection, hormonal issue, or something else, improves the chances of a healthy pregnancy later.