False Pregnancy or Pseudopregnancy in Dogs

What is a false pregnancy?

Anatomy of the female dog's reproductive tract, including the ovaries, uterine horns, uterus, cervix, and vagina.False pregnancy, pseudopregnancy, phantom pregnancy, or pseudocyesis are all terms that refer to maternal (mothering) behaviors and physical signs of pregnancy following estrus ("heat") in an unspayed female dog that is not actually pregnant.

A false pregnancy may occur in a dog regardless of whether she was mated. Most intact female dogs show some signs of false pregnancy after estrus.

What are the signs of false pregnancy?

Signs of false pregnancy usually begin four to nine weeks after the previous heat period and mimic the signs of true pregnancy. These signs can occur at any age and do not necessarily follow every heat cycle. The severity of these signs varies between individuals and may vary from one cycle to the next in the same dog. 

The more common physical signs of false pregnancy include:

• Mammary gland enlargement (with or without milk production)
• Lethargy
• Periodic vomiting
• Fluid retention
• Decreased appetite without losing weight, likely due to retained fluid

Behavioral changes during false pregnancy may include:

• Nesting
• Mothering behavior
• Restlessness
• Decreased interest in physical activity
• Aggression
• Signs of false labor 
• Guarding toys or other small objects

If your dog shows these signs but could possibly have been mated, your veterinarian may perform an ultrasound or take X-rays to determine whether she is pregnant.

Why do these signs occur?

After estrus, a female dog's ovaries begin to produce hormones, regardless of whether she is pregnant. These hormones prepare the uterus for pregnancy and help maintain it. If the dog is pregnant, the hormones continue to be produced until shortly before the puppies are born. If she is not pregnant, hormone levels usually decline after four to six weeks.

In the early stages, increased hormone levels cause changes that resemble pregnancy. As hormone levels decline in a non-pregnant dog, they send signals to the body that stimulate false labor and mammary gland development. It is not known why these hormonal changes occur in a non-pregnant dog.

How is false pregnancy treated?

Most cases of false pregnancy are mild and do not require treatment since the symptoms resolve in approximately 14 to 21 days. If the dog appears physically ill or the behavioral changes are severe enough to cause concern, treatment may be needed.

Treatment addresses the symptoms and may include sedation to relieve anxiety and medications such as diuretics to reduce milk production or relieve fluid retention. Do not massage or milk the teats during a false pregnancy, as this will only encourage more milk production. In rare cases, hormonal treatment may be required.

If your dog is not used for breeding, ovariohysterectomy (spaying) is recommended to prevent future episodes. Ideally, this surgical sterilization should be performed after all signs have resolved. If your dog is spayed while she is experiencing signs of false pregnancy, signs may continue for several weeks, even though she has been spayed.