False pregnancy, also known as pseudopregnancy or pseudocyesis, is a condition in unspayed female dogs where they display maternal behaviors and physical signs of pregnancy following estrus or heat, but they are not actually pregnant. False pregnancy can occur in a dog regardless of whether or not she was mated, and the majority of intact female dogs will show some signs of false pregnancy after an estrus cycle. The signs of false pregnancy usually begin four to nine weeks after the previous heat period and mimic the signs of true pregnancy. The more common signs of pseudopregnancy include mammary gland enlargement with or without the production of milk, lethargy, periodic vomiting, and fluid retention. Dogs with false pregnancy often have a decreased appetite but seldom appear to lose weight, likely due to the amount of excess fluid retained. False pregnancy can last anywhere from one week to one month, and the symptoms can begin at any age or after any given estrus cycle. The causes of false pregnancy in dogs are normal hormonal changes that begin after every estrus cycle, which prepare the dogs body for pregnancy. False pregnancy in dogs resolves in 2-3 weeks without any treatment, and since it is due to a hormonal change, the treatment is usually not necessary. However, if the dog is experiencing discomfort or other complications, the veterinarian may prescribe medications to alleviate the symptoms.