, 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. Clinically, false pregnancy is most common in veterinary medicine (particularly in dogs and mice). False pregnancy in humans is less common, and may sometimes be purely psychological.
In Humans (Pseudocyesis)
Cases of pseudocyesis have been documented since antiquity. Hippocrates
gives us the first written account around 300 B.C. when he recorded 12 cases of women with the disorder. Mary Tudor
(1516-1558), Queen of England, was perhaps the most famous of western historical examples, who believed on several occasions that she was pregnant, when she was in fact not. Some even attribute the violence that gave her the nickname "Bloody Mary" to be a reaction to her disappointment on realising she was without child. Other medical historians believe that the queen's physicians mistook fibroid tumors
in her uterus for a pregnancy. John Mason Good
coined the term pseudocyesis
from the Greek words pseudes
(false) and kyesis
(pregnancy) in 1923.
More recently, pseudocyesis has received attention in popular culture. It has been featured in the television shows CSI: Crime Scene Investigation, Law and Order SVU, The Simpsons, General Hospital: Night Shift, and Grey's Anatomy, and in the films Who's Afraid of Virginia Woolf? and Oldboy.
Signs and symptoms
The symptoms of pseudocyesis are similar to the symptoms of true pregnancy and are often hard to distinguish from it. Such natural signs as amenorrhoea
, morning sickness
, tender breasts, and weight gain may all be present. Many health care professionals can be deceived by the symptoms associated with pseudocyesis. Research shows that 18% of women with pseudocyesis were at one time diagnosed as pregnant by medical professionals.
The hallmark sign of pseudocyesis that is common to all cases is that the affected patient is convinced that she is pregnant. Abdominal distension is the most common physical symptom of pseudocyesis (60– 90%). The abdomen expands in the same manner as it does during pregnancy, so that the affected woman looks pregnant. This phenomenon is thought to be caused by buildup of gas, fat, feces, or urine. These symptoms often resolve under general anesthesia and the woman's abdomen returns to its normal size.
The second most common physical sign of pseudocyesis is menstrual irregularity (50–90%). Women are also reported to experience the sensation of fetal movements known as quickening, even though there is no fetus present (50%-75%). Other common signs and symptoms include gastrointestinal symptoms, breast changes or secretions, labor pains, uterine enlargement, and softening of the cervix. One percent of women eventually experience false labor.
To be diagnosed as true pseudocyesis, the woman must actually believe that she is pregnant. When a woman intentionally and consciously feigns pregnancy, it is termed a simulated pregnancy.
There are various explanations, none of which are universally accepted. Psychodynamic
theories attribute the false pregnancy to emotional conflict. It is thought that an intense desire to become pregnant, or an intense fear of becoming pregnant, can create internal conflicts and changes in the endocrine system, which may explain some of the symptoms of pseudocyesis. Another theory concerns wish-fulfillment. It holds that if a woman desires pregnancy badly enough she may interpret minor changes in her body as signs of pregnancy. Proposed biological mechanisms include the effect of stress on the hypothalamo-pituitary-adrenal axis
, weight gain and the movement of intestinal gas.
The rate of pseudocyesis in the United States has declined significantly in the past century. In the 1940s there was one occurrence for approximately every 250 pregnancies. This rate has since dropped to between one and six occurrences for every 22,000 births (http://www.womens-health.co.uk/false_pregnancy.html). The average age of the affected woman is 33, though cases have been reported for women as young as 6-1/2 and as old as 79. More than two-thirds of women who experience pseudocyesis are married, and about one-third have been pregnant at least once. Women who have been victims of incest may be at greater risk for developing pseudocyesis.
Because pseudocyesis is not known to have a direct underlying physical cause, there are no general recommendations regarding treatment with medications. In some cases, however, the patient may be given medications for such symptoms as the cessation of menstruation. Because most patients with pseudocyesis have underlying psychological problems, they should be referred to a psychotherapist
for the treatment of these problems. It is important at the same time, however, for the treating professional not to minimize the reality of the patient's physical symptoms. The treatment that has had the most success is demonstrating to the patient that she is not really pregnant by the use of ultrasound
or other imaging techniques. There have been reports of patients being cured of pseudocyesis by hypnosis
, or after nine months of symptoms, by experiencing "hysterical childbirth," but there are few data available on the effectiveness of these or similar procedures.
In other mammals (Pseudopregnancy)
The corpus luteum (the remains of an ovulated ovarian follicle) is responsible for the development of maternal behavior and lactation, which are mediated by the continued production of progesterone by the corpus luteum through some or all of pregnancy. In most species the corpus luteum is degraded in the absence of a pregnancy. However, in some species, the corpus luteum may persist in the absence of pregnancy and cause "pseudopregnancy", in which the female will exhibit clinical signs of pregnancy.
become pseudopregnant following an estrus
phase in which the bitch
is not bred, or in which the bitch
is bred by an infertile male. Most species require signals from an embryo (such as IFN-τ
) to alert the female's body of a pregnancy. This maternal recognition of pregnancy will cause persistence of the corpus luteum and the development of characteristics and behaviors necessary to care for offspring. Limited research suggests that progesterone secretion is similar in pregnant and non-pregnant bitches, so veterinary researchers hypothesize that dogs may not require molecular factors from the embryo for maternal recognition of pregnancy, and instead the corpus luteum persists regardless of pregnancy. Since the corpus luteum is not degraded, it will cause the development of maternal characteristics in the absence of pregnancy. Pseudopregnant bitches will develop their mammary glands
, and build nests
to varying degrees depending on breed. Although bitches usually only cycle once (monestrous bitches) or twice (diestrous bitches) per year, pseudopregnancy in dogs is common because the bitch does not have to be bred to become pseudopregnant.
Cats become pseudopregnant following an estrus in which the queen is bred by an infertile male. Queens are induced ovulators, meaning that they will only ovulate and produce a corpus luteum if they are bred. As in dogs, the corpus luteum persists as if the queen were pregnant, because the queen's body cannot distinguish between the pregnant and non-pregnant state (aside from the initial mechanical trigger of coitus). Pseudopregnant queens will develop their mammary glands, lactate, and build nests. Pseudopregnancy in cats is uncommon as the queen must be bred by an infertile male to become pseudopregnant, compounded by the fact that cats are seasonal breeders.
become pseudopregnant following an estrus in which the female is bred by an infertile male. Like dogs, mice
are spontaneous ovulators
. However, they will not become pseudopregnant following an estrus in which the female is not bred because the corpus luteum will degrade rapidly in the absence of coitus
. When the female is bred by an infertile male, the corpus luteum persists without an embryo, leading to pseudopregnancy. The female will develop mammary glands
, and build nests
in the pseudopregnant state. Pseudopregnancy in mice is somewhat common in the research setting because it is often induced for study, but is uncommon in wild mice because most wild males are fertile and will genuinely impregnate the female.