False Pregnancy (Pseudopregnancy)

What is it?

False (phantom) pregnancy is a mix of mothering behavior and physical signs of pregnancy in an unspayed female who is not pregnant. It is caused by normal hormone changes after heat and can happen whether or not she was mated. Most unspayed females show some signs after heat, and severity can vary from cycle to cycle.

What signs should I watch for?

Signs usually start four to nine weeks after heat and can include enlarged mammary glands with or without milk, weight gain or an enlarged belly, lethargy, occasional vomiting, fluid retention, and a decreased appetite. Behavior changes include nesting, mothering or guarding toys and other objects, restlessness, less interest in activity, false labor, and occasionally aggression.

How is it diagnosed and treated?

If she could have been mated, your veterinarian can check for true pregnancy with ultrasound or X-rays. Most cases are mild and need no treatment because signs fade in about 14 to 21 days. If she seems physically ill or the behavior changes are a concern, treatment may include medication for anxiety or to reduce milk and fluid, and rarely hormonal treatment. Do not massage or milk the teats, which only increases milk production.

Can it be prevented, and what's the outlook?

If she will not be bred, spaying is recommended to prevent future episodes, ideally after all signs have resolved; spaying during a false pregnancy can make signs last several weeks longer.