Pseudopregnancy: when the body mimics pregnancy without a fetus

Dear Editor,

Pseudopregnancy is derived from a Greek word, “pseudocyesis” in which pseudo means “false” and kyesis means “pregnancy.” Development of a sign and symptoms of pregnancy without the presence of an embryo or fetus.^[1^] It can occur in humans and animals, mainly in rats, rabbits, and cats. As per the epidemiological data, the rate of pseudopregnancy is declining nowadays, there are 1 to 6 cases per 22 000 births^[2^], and it is mostly found in patients between the ages of 16 to 40 years.^[2,3^] As per the data, 80% of women cases of pseudopregnancy are married^[3^]. Most of the cases are reported from developing countries such as India, and Saharan Africa. The occurrence rate in Africa is 1 of every 344 pregnancies^[3^]. The signs and symptoms include nausea, vomiting, delayed menstrual periods, increased uterus size, enlarged mammary glands with milk production, weight gain, polyuria (frequent and more urination), polyphagia (increased appetite), and a feeling of moving fetus. It can be caused by hormonal disturbance, trauma, stress, and psychological factors such as a strong desire for pregnancy. Apart from women, men also have a symptom of pregnancy called “couvade syndrome” or a sympathetic pregnancy^[4^]. Pseudopregnancy can also be referred to as a delusional pregnancy, but these two conditions are a little different, delusional pregnancy is referred to as a pregnancy in which there are no physical signs of pregnancy, it is due to a psychiatric disorder, but false pregnancy can also be delusional. In animals, the additional clinical signs observed were, nesting, over-affection, protectiveness, anorexia and over-defensiveness^[5^]. The symptoms associated with pseudo-pregnancy are described in Fig. 1. The article aims to raise awareness about this rare condition and its psychological and physiological underpinnings. The article also helps us understand the differences between false pregnancy and similar problems, like when someone believes they’re pregnant when they’re not, or when a partner experiences pregnancy-like symptoms. By explaining the signs, mental aspects, and hormone changes involved, the article wants to teach people about false pregnancy and encourage more research to find better ways to diagnose and treat it. PubMed, Scopus, and Google Scholar were used as search engines to search the articles with key words like “Pseudopregnancy,” “False pregnancy,” “Pseudocyesis,” “Phantom pregnancy,” “Couvade syndrome (sympathetic pregnancy),” “Delusional pregnancy,” “Psychological factors in pseudopregnancy,” and “Hormonal disturbances in false pregnancy,” then we selected the article after the abstract screening.

Figure 1.

An overview of symptoms associated with pseudopregnancy. Created using Napkin AI.

The detailed mechanism of pseudopregnancy cannot be completely understood, but as described earlier a psychiatric and endocrine component may have a role. The physiochemical disturbance leads to stress, anticipation, and general behavior disturbance, due to hormonal imbalance^[6^].

An increased level of prolactin leads to many symptoms of pregnancy such as amenorrhea, and galactorrhoea, and a higher level affects the CNS, leading to the sensation of fetal movement and pain^[7^]. The prolactin level increased either by two possibilities, from increased receptor sensitivity for prolactin or molecular variants having high bioactivity to immunoreactivity ratio towards prolactin. However, it is not an ideal parameter to consider, because the prolactin level is not always high in pseudopregnancy, one study found in animals that, there were no significant differences in serum prolactin levels during 13 out of 16 weeks in pseudo-pregnant and non-pseudo-pregnant bitches^[8^]. An LH (luteinizing hormone) and FSH (follicle stimulating hormone) increased and especially the frequency of LH surge is increased elevated T levels. The plasma level of norepinephrine is increased due to depression, which leads to activating the sympathetic system, in rodents, chronic physiological stress is associated with reduced brain dopamine and norepinephrine activity^[9^]. Enlargement of the abdomen and labor pain is due to increased sympathetic activity. As per the study, the distended abdomen remains bloated for months and immediately disappears, with or without the release of flatus^[10^]. In animals, the endocrine terminology is almost similar to humans, falling progesterone levels and increased prolactin levels associated with the late diestrus phase, feeling discomfort and mammary gland enlargement are clinical signs of it^[11^]. Sometimes, to increase animal models for research, researchers induced pseudo-pregnancy in animals using sonic vibration. Kaneko et al induced pseudopregnancy in female rats using artificial stimulation. The oestrus cycle of females continuously monitored who exhibited soliciting behavior during the proestrus stage after sonic vibrations artificially stimulated them. This study was carried out in proestrus females aged 10–14 weeks by inserting a fluoro resin probe into the vagina of the female. This pseudopregnant female was produced by mating with vasectomized male rats. After artificial stimulation, the females remained in the dioestrus stage for at least 14 days. The study showed that, of fresh 2-cell embryos that transferred into the oviducts of females after artificial stimulation, 56% of embryos were implanted and 50% were developed into offspring. This study successfully induced pseudopregnancy by using sonic vibration^[12^].

Diagnosis has been carried out based on clinical signs and symptoms, by pelvic examination, blood or urine pregnancy test, and ultrasound^[13^]. A pelvic examination is performed to show if conception has occurred or not, blood and urine test determines hormone levels, radiography, and ultrasound are for the examination of the fetus. Ultrasound is one of the direct examination techniques with high accuracy, it can detect if the tumor or fibroids are present or not. Bromocriptine, a dopamine agonist with a dose of 30 µg/kg/day for 16 days and 10 µg/kg/day to 10 days has been given to reduce prolactin levels^[14^].

Tranquilizers (diazepam, phenothiazine) were given to animals (dogs, mice) to normalize the behavior changes. But, now it is not recommended because it increases prolactin level^[15^]. Dopamine receptor agonist, cabergoline (dose 5 µg/kg/day) for 5 to 10 days orally^[16^] and serotonin antagonist metergoline (0.1 mg/kg orally twice a day for 8 to 10 days)^[17^] has been given to animals to reduce prolactin levels. One case study resulted that, the dose of diazepam was 10 mg/day for 5 days, cabergoline 0.5 mg (1/5th) tablet/ day for 7 days, and liv-52 syrup 2 t.s.f for 15 days of treatment normalize the mammary gland size, inhibited the ejection of milk and other symptoms disappeared^[18^]. Estrogen should not be given because it leads to bone marrow suppression^[19^]. Mibolerone was given for 5 days at a dose of 16mcg/kg/day, and megestrol acetate with a dose of 2.5 mg/kg/day for up to 8 days was given as a treatment. Among them, megestrol acetate is the only approved drug for false pregnancy, but long-term use may cause pyometra^[11^]. The permanent cure in animals (dogs) is ovariohysterectomy (surgical removal of ovaries and uterus)^[20^].

Despite the availability of research and clinical trials comparatively less on this topic, a case study of pseudo-pregnancy in a 48-year-old widowed menopausal woman reported by Sharma et al^[21^]. They observed all possible symptoms of pregnancy in women from the last 5 months, and upon clinical evaluation these movements were related to non-specific bowel movements. Before 10 years she was diagnosed with an HIV-positive test, then after three years, she got a positive urine pregnancy diagnostic test, then at 3 months of gestation, an ultrasound examination did not show any products of conception, and her abdominal examination revealed a soft, non-tender, distended abdomen with no palpable fundus or fetal parts and no fetal heart sounds. After constant negative urine pregnancy tests, and evaluation of the possibility of pregnancy and neuropsychiatric manifestations of HIV-AIDS, the patient has been started on the oral tablet of aripiprazole 5, 10, and 15 mg gradually, lastly, she was convinced that her symptoms could be related to lifestyle and dietary changes only^[21^].

Although “pseudopregnancy” is a clinical condition, a limited number of humans and animals are affected by this condition, however, the detailed pathophysiology behind this condition is not known yet, psychological and behavioral changes, endocrine factors, and hormones mainly responsible for this situation, but there are no approved clinical trials on a human to evolve its physiology, depth research should be required to treatment and prevention of this condition. Especially in animals, some case studies have been available, but they do not give the actual dosage, and still less data is available on the accuracy of detecting the behavior changes. In the future, more detailed study is required in all the pathological data for the betterment of humans and animals.

Ethical approval

Not applicable.

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No funding was received.

Author contributions

V.P.C.: conceptualization, writing original draft, and supervision; D.A.V: data collection, writing original draft, and supervision; A.K: resources, writing review, and editing; S.S: writing review and editing, supervision.

Conflict of interest disclosure

The authors declare that they have no conflict of interest.

Guarantor

V.P.C.

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None.

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Not commissioned, externally peer-reviewed.

Data availability

The data in this correspondence article is not sensitive and is accessible in the public domain.