The science of phantom pregnancies: a very real—and very rare—condition

The uncommon disorder can cause a woman’s body to mimic signs of pregnancy

In April 1555, Queen Mary I—better known to history as “Bloody Mary”—went into seclusion as she awaited the birth of her first child. At 38, the eldest daughter of King Henry XIII desperately needed an heir, preferably male, to secure an alliance with Spain and continued Catholic rule in England. The stakes were high.

Still, both Mary and the nation were optimistic. The year after she’d married Philip II of Spain, the Queen looked pregnant: Her breasts and belly had swelled, and she reported morning sickness and movement in her womb. As such, the nursery was prepared, wet nurses were on call, and announcement letters were prepared and signed, leaving just the date of delivery and sex of the child to be filled in.

Yet “as the weeks passed, the mood became one of despair,” writes Anna Whitlock, author of Mary Tudor: Princess, Bastard, Queen. Rumors spread the Queen was dead, or that the child had died, and another would be swapped in its place.

The truth was less scandalous: Despite all appearances to the contrary, Mary had never been pregnant to begin with, having the misfortune of being history’s first well-documented case of a very rare phenomenon called pseudocyesis.

Sometimes called false, hysterical, phantom, or delusional pregnancy, pseudocyesis manifests most or all symptoms of pregnancy, but no fetus.

For instance, a sufferer doesn’t have a menstrual period, her breasts get larger and may even express milk, and her stomach is distended, says Mary Seeman, professor emerita at the University of Toronto’s Department of Psychiatry. Such physical manifestations also occur alongside fatigue, nausea, and frequent urination.

“Her body is acting pregnant, so she believes she’s pregnant, but she’s not otherwise delusional,” says Seeman, who’s long studied the mental disorder.

Most cases have psychological and physiological elements. The American Psychiatric Association’s diagnostic manual, DSM-5-TR, places pseudocyesis in the category of other specified somatic symptom and related disorder, along with other difficult-to-categorize disorders such as illness anxiety disorder (aka hypochondria) or factitious disorder (aka Munchausen’s).

How common is pseudocyesis?

In 2007, a review in the International Journal of Reproductive BioMedicine estimated there are between one and six cases per 22,000 pregnancies in the United States. That’s a huge drop since 1940, when the statistic was one case of pseudocyesis per 250 pregnancies—exactly the likelihood of natural twins.

These numbers climb drastically outside the U.S.

“There are parts of Africa, for example, where pregnancy is very valued and medical care is hard to access, so pseudocyesis is not uncommon,” says Seeman, who has encountered about 20 cases in her practice since 1960.

Because of modern medicine and the wide availability of ultrasounds, very few cases of pseudocyesis today go undetected until apparent “delivery.”

Those that do, like Queen Mary’s, often make headlines. In 2014, for example, a Quebec woman convinced her town she was expecting quintuplets. At 34 weeks, she went to the hospital to deliver—where a nurse discovered there were no babies at all.

“Pseudocyesis is notoriously difficult to study,” says Seeman, mostly due to its rarity and the complexities of the patient’s mental health. But there’s one common thread: “The patient usually desperately wants to be pregnant.”

Besides a baby, pregnancy may also provide a woman with particular benefits, such as better care, attention, and even respect. Unsurprisingly, Seeman says, pseudocyesis occurs more often in cultures where married women are expected to produce children.

A still-mysterious condition

“The medical establishment, even within the field of OB-GYN, does not have a good understanding of pseudocyesis,” says Shannon M. Clark, a maternal fetal medicine specialist at the University of Texas Medical Branch who has seen cases of false pregnancy.

Understanding what’s happening in the body of a woman with pseudocyesis would help both treat the condition and reduce the stigma of the sufferer being labeled as “crazy,” Clark says.

Pop culture hasn’t helped: For instance, the lead character in the upcoming TV show American Horror Story: Delicate experiences violent and terrifying hallucinations during a supposed pregnancy, an example of a cinematic trope called “pregnancy horror.”

As always, real life isn’t so dramatic. Though changes in hormones such as prolactin, estrogen, and progesterone can occur, there’s no clear pattern or elevation of hormone levels associated with the condition, Clark says.

And the psychiatric drugs doctors might prescribe to a patient, meanwhile, could actually worsen her health.

For instance, some antipsychotic drugs raise levels of prolactin, a hormone responsible for lactation, which may just further convince the patient—and her body—that she’s indeed pregnant.

Prolactin levels also increase with stress, and “it’s safe to say that a woman who’s convinced she’s pregnant when a test repeatedly says she’s not is certainly under severe stress,” says Seeman.

Who suffers from pseudocyesis?

Immense stress was likely the trigger for Queen Mary’s pseudocyesis, experts say.

Nearly a year into her so-called pregnancy, Mary finally emerged from her chamber and no one spoke of it again (at least officially). She died three years later, childless, and the throne passed to her Protestant half-sister, Elizabeth I.

“Pseudocyesis affects people from all ethnic, racial, and socioeconomic groups,” notes Clark. And although it’s most common in those aged 20 to 39, it can occur in post-menopausal women as well.

Pseudocyesis in men is even scarcer, though medical literature documented examples of the phenomenon in two American men, in 1984 and 1995. In April 2022, scientists reported a 28-year-old American transgender woman who presented as pregnant with twins.

Unlike many cisgender women with pseudocyesis, these three individuals all demonstrated severe mental illnesses.

A widespread denial

Just as Queen Mary did for nearly a year in 1555, modern patients with pseudocyesis will not accept evidence that they’re not pregnant, Seeman says.

“They might think their husband doesn’t want them to be pregnant, that he’s colluding with the doctor or hospital. They might think their in-laws are involved. I’ve seen people who believe the doctor has impregnated her but won’t admit it,” she says.

“These delusions can take so many forms because the person can’t accept anyone’s reality but their own. Their reality is they look and feel pregnant, so as far as they’re concerned, they are.”

Fortunately, the medical establishment has started treating these unusual cases with increased interest and sensitivity, Seeman says.

“General psychiatry is paying more attention to issues that they used to consider ‘just’ women’s syndromes,” she says.

From the rest of us, adds Clark, “more understanding and empathy and less judgment and shaming are needed on all fronts.”