False pregnancy, or pseudocyesis, refers to a rare condition where a patient is not actually pregnant but believes she is. The diagnosis falls into the category of somatic symptom and related disorders, wherein this belief of being pregnant is brought on by misinterpretation of a constellation of symptoms that can be associated with pregnancy. For instance, a patient may have irregular or absent menses in conjunction with weight gain, breast tenderness, nausea, abdominal enlargement, or other symptoms and then believe she must be pregnant. As the disorder deepens, she may experience symptoms that she interprets as fetal movement and labor pains.

It is unclear why some may experience this phantom pregnancy, although predisposing risk factors include history of miscarriage, infertility, and loss of a child, as well as coexisting mental conditions. Other potential factors include psychiatric medications that may induce amenorrhea or elevated prolactin levels as a side effect as well as ovarian tumors.

Cases tend to occur more often in populations where there is a specific focus on childbearing as central to a woman's existence. It is thought that stress from that burden, in conjunction with other pressures, can spur on an episode.