There are many reproductive diseases that can affect female dogs. The most common diseases are discussed in this section.
Abnormal or Difficult Birth (Dystocia)
Many factors can cause a difficult birth, including uterine problems, a too-small birth canal, an oversized fetus, or abnormal position of the fetus during birth. Dystocia should be considered in any of the following situations: 1) dogs that have a history of dystocia; 2) birth that does not occur within 24 hours of a drop in rectal temperature (a sign of impending birth); 3) continuous strong contraction for more than 20 to 30 minutes with no birth; 4) active labor for more than 1 to 2 hours without a birth; 5) a resting period during labor that lasts more than 2 to 4 hours; 6) obvious illness in the mother; and 7) abnormal discharge from the vulvar area. Once the cause is identified, the appropriate treatment can be determined. X-rays or ultrasonography can show how many fetuses are present. Medication may help the labor progress if the mother and fetuses are still in stable condition and there is no obstruction. Surgery (cesarean section) is performed if the mother or the fetuses are not stable or there is an obstruction.
False Pregnancy (Pseudopregnancy)
False pregnancy is common in female dogs. It occurs at the end of the heat cycle and is characterized by swelling of the mammary glands, milk production, and behavioral changes. Some dogs behave as if delivery has occurred and “mother” by nesting inanimate objects and refusing to eat. Your veterinarian will eliminate the possibility of true pregnancy by the medical history, physical examination, and x‑rays or ultrasonography. Treatment is often not recommended because the condition usually ends on its own in 1 to 3 weeks. You should not milk out the mammary glands, because this will only stimulate production of more milk. Treatment can be given to animals that are uncomfortable because of milk production or to those with behavior that is troublesome.
These fluid-filled structures develop within the ovary and lead to prolonged secretion of estrogen and continuous signs of estrus (heat) and attractiveness to males. Ovulation may not occur during these abnormal estrous cycles. Follicular cysts should be suspected in any dog showing signs of heat for more than 40 days. The condition is diagnosed through ultrasonography and laboratory tests. The treatment of choice is removal of the ovaries and uterus, which is curative. If the dog is to be bred, administration of drugs that cause ovulation might resolve the condition; however, these dogs must be monitored closely for uterine disease.
Mastitis is inflammation of the mammary gland(s) that occurs in dogs after giving birth. It is caused by a bacterial infection. Risk factors for developing mastitis include poor sanitary conditions, trauma inflicted by offspring, and whole-body infection. Mastitis may involve a single gland or multiple glands. Milk is usually abnormal in color or consistency. The affected glands are hot and painful. If mastitis progresses to a generalized infection, signs of illness such as fever, depression, poor appetite, and lethargy may be seen. The disease is diagnosed based on the physical examination and the dog's medical history. Your veterinarian may test for bacteria to determine which antibiotic to use in cases of infective mastitis. Warm compresses should be applied to the affected glands 4 to 6 times daily, and the puppies should be encouraged to nurse from these glands. An abscessed mammary gland should be lanced, drained, and treated as an open wound.
At the time of weaning, there may be an abundance of milk and glands that are warm, swollen, and painful to touch, but the dog should remain alert and healthy. Lactation can be diminished by reducing food and water intake.
Metritis is inflammation of the uterus that occurs after pregnancy. It is usually caused by bacterial infection. Factors such as prolonged delivery and retained fetuses or placentas may cause metritis. Escherichia coli bacteria are a common cause of infection of the uterus. The primary sign of infection is a pus-like discharge from the vulva. Female dogs with metritis are usually depressed, feverish, and may neglect their offspring. Pups may become restless and cry incessantly. The infection is diagnosed through physical examination, ultrasonography, and laboratory tests. Treatment includes administering fluids, supportive care, and antibiotics.
Ovarian Remnant Syndrome
Ovarian remnant syndrome is caused by ovarian tissue that was left behind when a dog was spayed. This is a complication of the surgery. The most common signs are those of heat (swelling of the vulva, flagging, and standing to be mounted). The ovarian tissue is removed by surgery.
Pyometra is a bacterial infection of the uterus due to hormonal changes in unspayed dogs. It is reported primarily in dogs more than 5 years old, and tends to occur 4 to 6 weeks after estrus. After estrus, the level of progesterone stays high to prepare the uterus for pregnancy by thickening its surface. If pregnancy does not occur for several cycles, the lining inside the uterus continues to thicken and cysts will form within the uterus. These cysts secrete fluids providing an ideal environment for bacterial infection. Pyometra can occur due to administration of progesterone-based medication.
The signs are variable and include lethargy, poor appetite, and vomiting. When the cervix is open, a discharge of pus, often containing blood, is present. When the cervix is closed there is no discharge and the large uterus may cause abdominal enlargement. Signs can progress rapidly to shock and death. The infection is diagnosed by physical examination, determination of the nature of the discharge, ultrasonography, x-rays, and laboratory and blood tests.
Removal of the ovaries and uterus are the recommended treatment in most cases. For animals that will be bred in the future, antibiotics and prostaglandin can be administered. Animals should be re‑-examined 2 weeks after completion of medical treatment to ensure complete emptying of the discharge from the uterus. Dogs with a history of pyometra should be bred on the next heat cycle after treatment, as pyometra will eventually recur. Affected dogs should be spayed as soon as their breeding life is over.
Subinvolution of Placental Sites
This disorder occurs after pregnancy as a result of abnormal repair of the lining of the uterus (where the placenta was attached). After giving birth, the uterus slowly returns to its normal size in a process called involution. Normally, a bloody discharge accompanies this process for up to 16 weeks after birth. In some dogs, the discharge lasts much longer. The condition is most common in dogs less than 3 years old after their first litter. There are no signs except for discharge from the uterus that contains blood. Blood loss is not severe with this condition. It resolves on its own and usually does not recur. Spaying is curative but it is not necessary if there is a desire to breed the dog again.
Vaginal Overgrowth (Vaginal Prolapse, Vaginal Hypertrophy)
In vaginal overgrowth, the vaginal tissue becomes swollen during estrus (heat). The swollen vaginal tissue may be seen through the vulva. This condition is caused by estrogen and is most common in young dogs. The disease is diagnosed through the medical history and physical examination. Vaginal overgrowth resolves on its own as soon as the estrogen-producing phase of the cycle is over. However, it usually recurs with every heat. Treatment may include daily cleansing of the affected area, prevention of trauma, and antibiotic ointment. An Elizabethan collar (a large funnel-shaped collar that prevents the dog from licking itself) may be necessary to prevent self‑trauma. These dogs may be bred by artificial insemination, but the female puppies may also be prone to develop this condition.
Inflammation of the vagina may occur before puberty or in mature dogs. It is especially common in puppies. Vaginitis is primarily due to bacterial infection. Viral infections, vaginal foreign bodies, or cancer may also cause vaginitis. The most common sign is discharge from the vulva. Animals may also lick the vulva. The disease is diagnosed through physical examination and laboratory tests. Vaginitis in puppies usually resolves on its own when the pup has reached physical maturity. In the case of a persistent infection, antibiotics are administered. Estrogen treatment may be beneficial in the treatment of spayed dogs.
Last full review/revision July 2011 by Cheri A. Johnson, DVM, MS, DACVIM (Small Animal); Brad E. Seguin, DVM, MS, PhD DACT; Autumn P. Davidson, DVM, MS, DACVIM; Fabio Del Piero, DVM, DACVP, PhD; James A. Flanders, DVM, DACVS; Mushtaq A. Memon, BVSc, MS, PhD, DACT; Paul Nicoletti, DVM, MS, DACVPM; Robert C. Rosenthal, DVM, PhD, DACVIM (Small Animal, Oncology), DACVR (Radiation Oncology)