| Hysterical pregnancy, also called false, phantom or spurious pregnancy, is known medically as pseudocyesis. It is a condition in which a woman becomes convinced she is pregnant, to the degree that she actually exhibits symptoms: pseudocyesis can produce hormonal changes sufficient to fool pregnancy tests, produce amenorrhea, provoke bloating, and cause spasms simulating fetal movement. Symptoms can be convincing enough to fool experienced doctors and nurses.
In the middle ages there were many cases of nuns becoming convinced they were pregnant with the seed of Christ after swallowing a Communion wafer.
One of the most famous cases of pseudocyesis was Joanna Southcott. In London in 1814 she announced that she was immaculately pregnant with the child Shiloh, the new Savior of Mankind. Her breasts and belly swelled, many witnesses testified to having felt the child move, and seventeen of twenty-one examining doctors were persuaded of the pregnancy. Crowds flocked to London with gifts for the child. The delivery date was pushed further and further back, however, until Southcott finally died of an opium overdose, and it was revealed that she had never been pregnant at all.
Modern psychologists posit several explanations for the condition, including religious fervor, high-pressure social demands to become pregnant, dread of menopause, or as a coping mechanism to deal with past sexual abuse. | 
