Simplify the following text for a Grade 12 native English-speaking person.
Original: False pregnancy or hysterical pregnancy , most commonly termed pseudocyesis in humans and pseudopregnancy in other mammals , is the appearance of clinical and\/or subclinical signs and symptoms associated with pregnancy when the person or animal is not pregnant .
Simplified: A false pregnancy , hysterical pregnancy or pseudopregnancy is when a mammal shows some of the symptoms associated with a pregnancy , but without being pregnant .