If you ever doubt the power of the mind-body connection, the phenomena of pseudocyesis is a powerful example of its reality. The medical term is pseudocyesis, but the phenomena has also been called false pregnancy, delusional pregnancy, and phantom pregnancy. [1,2]
A woman experiencing a false pregnancy may experience morning sickness, loss her periods, swelling of her belly, swollen breasts, milk leaking from her breasts, and even the sensation of fetal movement. It has been estimated that up to 6 out of 22,000 pregnancies turn out to be false pregnancies. Women who experience false pregnancy truly believe that they are pregnant. [2,3]
False pregnancy is rare in developed countries but is fairly common in developing countries like Africa, India, and some Islamic countries. These are countries where cultural pressure to fulfill the role of motherhood is very strong. False pregnancy is mysterious. Psychological causes are probably the main causes, but physical causes may contribute in some cases. 
Perhaps the most famous case of false pregnancy in history is the phantom pregnancy of Mary Tudor, daughter of Henry the Eighth, who became queen of England at the age of 38 in 1553. There was enormous pressure on her to bear a child and an heir to the throne. A pregnancy was announced in 1555, and Mary developed all the signs of pregnancy. Her doctors believed her to be pregnant. Of course, there were no ultrasounds or hormone tests to prove otherwise. It was only long after her due date that the phantom pregnancy was discovered. She had another false pregnancy in 1557, and died a debilitated and broken woman a year later at age 42. [2,4]
Psychological vs. Physical Causes
For many women in developing countries, pregnancy is a status symbol that can lead to respect, better treatment, and more support. For example, in Islam, a husband cannot divorce a pregnant wife. 
In developed countries, false pregnancy often occurs in women who have dealt with infertility, are approaching menopause, and have endured stressful life experiences. It may be an attempt to deal with the sadness of infertility and loss of the possibility of fertility. Some stress factors that have been linked to false pregnancy include a history of miscarriage, depression, sexual abuse, and mental illness. [2,3]
Physical causes that may mimic pregnancy can contribute to the belief in a false pregnancy. These include conditions that cause the belly to swell, like abdominal cysts or tumors, and conditions that cause loss of menstrual periods (amenorrhea). One recently recognized contributor might be an elevation in the hormone prolactin. 
Prolactin is a hormone produced in the brain that stimulates a woman to produce breast milk. High levels of prolactin can produce many symptoms of pregnancy, including breast swelling, milk leaking, and amenorrhea. Elevated levels of prolactin can occur from psychological stress and can be caused by many common medications. One reason why false pregnancy may be more common in women with mental illness is that antipsychotic drugs may raise prolactin levels. 
In many cases, false pregnancy can be a pure, mind-body phenomena. The belief in pregnancy may be strong enough to cause the symptoms. In fact, false pregnancy can even occur in men. This condition – called sympathetic pregnancy or couvade – is seen in men who have a pregnant partner. Couvade is a French word for lying down. In some primitive cultures, men would be expected to lie down and wait for labor along with their mate. Men with couvade may experience morning sickness, bloating, backaches, reduced libido, and depression. [1,5]
Treatment of False Pregnancy
In modern cultures, the same tests used to diagnose pregnancy also diagnose false pregnancy. Hormone tests do not show a rise in pregnancy hormones. A physical exam and ultrasound do not show the presence of a baby in the womb. [1,3]
This diagnosis can be heartbreaking for some women. In fact, many women with false pregnancy will continue to believe they are pregnant in the face of overwhelming evidence that they are not. They may hold on to their belief through nine months or beyond. Part of the diagnosis is to rule out any physical causes for pregnancy symptoms, medications that may be stimulating prolactin, and the presence of any serious underlying mental illness. [2,3]
In some countries of sub-Saharan Africa, infertility is always blamed on the woman. In reality, infertility is just as likely to be caused by the male. In these countries, “infertile women” may experience violence and abuse. The most important treatment is understanding and psychological support. False pregnancy is a real condition. It may be a call for help. It should never be a call for shame or ridicule. [2,3]
- American Pregnancy Association, What Exactly Is A False Pregnancy Or Pseudocyesis?
- World Journal of Clinical Cases, Pseudocyesis, delusional pregnancy, and psychosis: The birth of a delusion.
- Psychology Today, The Heartbreaking Phenomena of False Pregnancy.
- Doctor’s Review, An Heir-raising experience.
- Mayo Clinic, Pregnancy week by week.