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True or False Pregnancy

Donate False pregnancies are not only real, they're probably more complex than you imagined.  

by Brian Dunning

Filed under General Science, Health

Skeptoid Podcast #572
May 23, 2017
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True or False Pregnancy

The year was 1555, the place, Hampton Court Palace, Richmond upon Thames, London. Queen Mary the First was so fervently earning her posthumous nickname Bloody Mary by burning heretics at the stake by the hundreds. But while she was taking so many lives, she was also trying to create one. Shortly after her marriage to Spain's Prince Philip, her physicians announced that the Queen was expecting. Her belly distended, her periods stopped, she gained weight, and she suffered from morning sickness. Nine months later she was ready to go. A month after that, she was still ready, but there was no baby. She spent the eleventh month largely sequestered, as murmurings swept the court that she was not actually pregnant. Indeed, there was no child. And then her abdomen receded, and she emerged, thin, heartbroken, humiliated. She became the most famous case of what we now call a false pregnancy. But is it just an urban legend, or do women sometimes actually have a pregnancy without the most important element?

It's called pseudocyesis, or false pregnancy. Over the years it's also been known as phantom pregnancy and hysterical pregnancy, a term that is today somewhat out of favor. The body undergoes all the hormonal changes that produce the characteristic symptoms of pregnancy, with the notable exception of the lack of a fetus. Pseudocyesis is hard to study because it's so rare in humans. In fact, it's so rare that we don't even have good numbers for how often it happens. Probably between 1 in 4,000 and 1 in 20,000 pregnancies turn out to be pseudocyetic, and much of the uncertainty comes from a lack of reporting of incomplete pregnancies, both miscarriages and false pregnancies. They really only ever make it into the medical records when they progress far enough to warrant a doctor's visit, so we never get data at all from so much of the world's population where prenatal care is uncommon or nonexistent.

I say it's rare in humans because it's actually more common in dogs and mice, and we also see it a lot in cats and pigs. Most of these cases are triggered when the female is bred with an infertile male. The corpus luteum is a structure in the ovary which produces the hormone progesterone throughout the term of the pregnancy, and which develops from an ovarian follicle that has released its egg. During heat, the corpus luteum may sometimes persist even if the egg was not fertilized. The protracted secretion of progesterone then causes all the changes in the animal's body that happen during pregnancy.

It's not clear if this same mechanism happens in humans or not. In fact, in most cases of pseudocyesis, the triggering cause is undetermined. However there are still different types. They're all interesting, and they all dash the popular stereotype of a crazy lady who wants a baby so badly that her brain tricks her body into thinking she has one. Although, as we'll see, there are cases where that's not as far from the truth as you might think.

The reason for that potential connection is illustrated in this first cause we'll look at, and it's one of the oldest known causes: intestinal gas. Gas can trigger a false pregnancy (and it's a good time to remind ourselves that this is exceptionally rare) in at least two ways. Sometimes gas can feel like something moving down there, and sometimes a whole lot of gas can produce a visible abdominal bulge. Occasionally, either or both of these can be mistaken for signs of a pregnancy.

But it takes a lot more than that to develop into a full-blown, systemic pseudopregnancy. And what that is is the incredibly complex and rich interrelationship between the neuroendocrine system and psychology. The short version is that emotions and hormones can affect one another, and hormones can cause changes in the body. The long version fills textbooks and is the subject of lots of ongoing study.

For a simple example, look at stress hormones. When we're under extreme stress, we go into hyperarousal, or the "fight or flight" response. All kinds of physical changes happen throughout the body, triggered mostly by the hormone adrenaline. Many hormones trigger the production of other hormones — all from that one emotion. Other emotional states can trigger the release of hormones too. In the right emotional state, and under the right conditions, given a sufficiently receptive stage in a woman's normal hormonal cycle, the domino effect of a body becoming pregnant can actually take place — even though there is no fetus. This is the working theory, anyway; though the number of variations and subtleties makes it virtually impossible for anyone to pinpoint any single cause of a pseudopregnancy. Simple intestinal gas can set the ball in motion, given the right emotional state and the right hormonal conditions.

Pseudocyesis was known in Queen Mary's time, as was gas as a potential cause. Giovanni Michiel, the Venetian ambassador to England, wrote much about Mary. During the eleventh month of her pregnancy, he wrote in a dispatch back to Venice:

...The hope of childbirth has so diminished that but little reliance can now be any longer placed on it.

...The chief personages here...have come to the conclusion...that the pregnancy will end in wind rather than anything else...

So even then, gas was the suspected cause of Mary's false pregnancy — and according to the scientific understanding of the day, a large release of said gas could end the false pregnancy. And beyond gas, simple weight gain is also hypothesized to have the ability to trigger the hormonal cascade, so long as the mother honestly interprets it as a sign of pregnancy, and the other conditions are in place.

Such a false pregnancy as this is termed — from the psychological perspective — a somatic symptom disorder. In more common psychological manifestations, a somatic symptom disorder is one in which you become excessively stressed over a physical complaint. It doesn't matter what the physical complaint is; it doesn't even matter whether it's a real physical problem or one that you simply believe yourself to have (e.g., you think you have an alien implant). It's usually something like chronic pain. Normal worry over such a thing magnifies into a psychological disorder when you devote excessive time and energy to worrying about it, or you have persistent or exaggerated thoughts about its seriousness, or your anxiety over it becomes disproportionate. Similarly, excessive motherly emotions combined with a mistaken (but honest) belief in pregnancy can be sufficient to trigger the hormonal reaction.

There is another variant to be aware of that's more in line with the stereotype of the crazy lady wanting to be pregnant, but that we do not classify as a type of pseudocyesis. This is the delusion of pregnancy, rarely found in schizophrenics. In this case, sufferers have a psychotic belief that they are pregnant, but do not display any of the physical changes. The brain is willing, in these cases, but the body is not. Here is from a case study published in 2012 in the Indian Journal of Psychological Medicine:

During the interview, she revealed a well-systematized delusion of pregnancy. In response to the specific question on pregnancy, she answered that she had a baby in her abdomen. She was convinced that she could feel the fetal movements. When asked to account for the flatness of her abdomen, she mentioned that her abdomen had remained flat even during her earlier pregnancies.

The most surprising variant is called Couvade syndrome, which is when it happens to men. All reported cases have been partners of expectant women. They experience the same physical changes in the body, though to a markedly lesser degree. Hormonally, it's perfectly plausible; but psychologically, it's less so. While men and women do have the ability to produce the same hormones, we do so in different amounts; and the husband of an expectant mother is not going to actually believe himself to be pregnant. Because the husband is not going to be able to have as strong an emotional trigger (due to his lack of belief in his own pregnancy), and is not going to be able to produce nearly as much progesterone, we typically see this syndrome mainly limited to symptoms such as nausea, sleep disruption, increased appetite, and back pain.

Interestingly, Couvade syndrome is much more common in certain remote indigenous societies found in Papua New Guinea, Thailand, and South America. From this we might conclude that these groups are those that have a cultural norm in which the husbands take a more sympathetically involved role in pregnancies than do men in more developed societies.

Birth announcements for Mary Tudor's young royal heir were prepared with blanks for the sex and date to be filled in. A nursery was built in Hampton Court Palace. And then, on April 30, 1555, all of London rang with the peal of church bells. There were celebrations in the street, for the news had spread that a baby boy had been born to Mary. But up in her chamber in the palace, the curtains were drawn and there was no celebration. Whatever was going on outside was merely the expression of some hopeful rumor. Mary was still quite ill. The days stretched to weeks, the weeks stretched to months. It was the anger of God, she believed, over the growth of the Protestant movement, and she ordered a fresh round of executions to satisfy His will. But no succor came, and Mary finally faced the fact that it had been a cruel phantom pregnancy. Outside, her rivals snickered and gloated. But inside, there was no joy. Mary spent weeks in a deep depression, curled in a ball, as she could now that her abdomen had shrunk back to normal. Her periods returned. She was devastated. Privately, the order went round that the pregnancy was never to be mentioned in her presence — an order that, by all accounts, was followed to the letter for the rest of her short life. She died three years later, just as another tantalizing, yet ultimately false, pregnancy was growing inside her. We don't know, but some experts think uterine or ovarian cancer may have killed Mary at the age of 42, and possibly been the cause of her two false pregnancies as well.

Far from the hysterical delusion of a madwoman, a false pregnancy is a spiteful and callous deceit that nature sometimes plays upon hopeful mothers. If you know someone to whom this has happened, give her a hug.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "True or False Pregnancy." Skeptoid Podcast. Skeptoid Media, 23 May 2017. Web. 20 May 2024. <>


References & Further Reading

Editors. "Men suffer from phantom pregnancy." BBC News. British Broadcasting Corporation, 14 Jun. 2007. Web. 19 May. 2017. <>

Rosenhek, J. "An Heir-Raising Experience." Doctor's Review. Parkhurst, 1 Aug. 2013. Web. 15 May. 2017. <>

Starkman, M., Marshall, J. "Pseudocyesis: psychologic and neuroendocrine interrelationships." Psychosomatic Medicine. 1 Jan. 1985, Volume 47, Number 1: 46-57.

Tarín, J., Hermenegildo, C., García-Pérez, M., Cano, A. "Endocrinology and physiology of pseudocyesis." Reproductive Biology and Endocrinology. 14 May 2013, Volume 11, Number 39.

The Crown. Calendar of State Papers Relating To English Affairs in the Archives of Venice, Volume 6, 1555-1558. London: Her Majesty's Stationery Office, 1877. 145-163.

Yadav, T., Balhara, Y., Kataria, D. "Pseudocyesis Versus Delusion of Pregnancy: Differential Diagnoses to be Kept in Mind." Indian Journal of Psychological Medicine. 1 Jan. 2012, Volume 34, Number 1: 82-84.


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