Canine False Pregnancy (Pseudopregnancy, Pseudocyesis)

Non-pregnant female dogs commonly display physical and behavioural signs consistent with pregnancy. This is infrequent in female cats. The abdomen may appear somewhat swollen and milk may be produced in the mammary glands. This is associated with hormonal imbalances and ovarian abnormalities, but it can also occur in spayed females. Signs of false pregnancy may be subtle and unnoticed. The bitch may redirect maternal urges by carrying toys or other objects, presumably surrogate offspring, to a nest she has prepared. She may be restless and irritable. Aggressiveness may be more easily provoked during this period, perhaps because of hormonal imbalances, though other factors are certainly involved. False pregnancy may resolve without treatment, but recurrence is common in subsequent "heat" cycles and complications are common. Medication may or may not temporarily resolve false pregnancy. Unless the pet is of particular breeding value, pronounced false pregnancy justifies spaying.

Clinical False Pregnancy

When false pregnancy persists it can be a nuisance. The female dog can show the following signs:

• Nesting
• Mothering inanimate objects
• Lactating (giving milk)
• Abdominal distension
• She can even appear to go into labor

Some female dogs are very sensitive to the hormonal fluctuations of the cycle. Diagnosis is made by history and physical examination rather than by blood test. The key is to find symptoms of pregnancy in a female dog who is not pregnant. Symptoms generally become noticeable 6 to 3 months after estrus.

Treatment

If symptoms are mild, treatment is unnecessary as the condition resolves within 3 weeks. It may be tempting to put warm compresses on the breasts or wrap them to prevent milk leakage causing stains in the house. It is important to remember that any touching of the mammary tissue is what stimulates milk production, so it is important to minimize tactile stimulation. If the female is licking herself, she may need an Elizabethan collar to minimize stimulation. If a more aggressive approach is needed, a diuretic such as furosemide can be prescribed. The idea is that mild dehydration will end the lactation. Some people may want to try water deprivation but this is potentially dangerous and should not be attempted without specific veterinary guidance.If this doesn’t work, hormonal medications can be used. Progesterone can be used but after the course of medication is complete, the false pregnancy recurs so this is not a good choice. Estrogens are also not a good choice as they bring the dog back into estrus symptoms. A week’s course of the male hormone mibolerone has generally been successful but the medication is no longer available. Hormones that inhibit prolactin (the hormone of milk production) are currently the best choices when medications are needed. Bromocriptine can be obtained from a compounding pharmacy and given until lactation ceases (about a week or two) but tends to cause upset stomach. Cabergoline has fewer side effects but is given similarly and tends to be more expensive. Both these medications will cause abortion if the dog actually turns out to be pregnant so it is important to be sure.

Spay During False Pregnancy?

It might seem like a good idea to spay the female to end the false pregnancy as spaying will remove the ovaries and the corpora lutea they carry. Unfortunately, this does not end the prolactin production from the pituitary gland so spaying may actually prolong the false pregnancy. It is best to wait until the false pregnancy is over and then spay her to prevent future episodes.