Hysterical pregnancy is a condition in which the brain is convinced the body is carrying a baby even though it is not. Pseudocyesis, the term the medical community uses for false pregnancy, affects one to six of every 22,000 live births, according to WebMD. The condition also affects men, although occurrence is very rare.
A woman experiencing pseudocyesis has many of the same symptoms as a pregnant woman. Some women stop menstruating and have distended abdomens. The brain signals the body to increase hormone levels, causing the patient to experience engorgement of the breasts and, in some cases, release colostrum. According to BabyCenter, hysterical pregnancy even causes contractions in some women.
WebMD reports that although an exact cause of the condition has not been identified, the symptoms of false pregnancy can often be traced back to a strong desire go get pregnant in women who've had multiple miscarriages, are infertile or are approaching menopause. Pseudocyesis is often triggered by a traumatic event, such as the loss of a spouse, according to BabyCenter.
The woman's desire for a baby is sometimes so great that her brain creates the physical symptoms of pregnancy in her body, according to BabyCenter. These false symptoms can be so strong that some women are convinced they see a baby during an ultrasound. Pseudocyesis has become less frequent as early pregnancy tests began to be available.