Dispelling Morning Sickness Myths–It’s Not What You Might Think

Hyperemesis gravidarum is not psychosomatic, nor is it caused by a hormone that doctors long thought was the culprit, research shows.

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Severe morning sickness during pregnancy, known as hyperemesis gravidarum or HG, is one of the most common reasons for hospitalization during early pregnancy. It’s a condition that can lead to dehydration and weight loss in expecting mothers and has been linked to poor outcomes in babies.

There is currently no cure for HG, and not much can be done for women with this poorly understood condition, other than treating them with intravenous fluids, electrolyte supplementation, antiemetic (anti-nausea) medications, and sometimes steroids. However, a discovery published in late 2023 about HG’s most likely cause may lead to better treatments, and possibly its prevention, in the near future.

The discovery came when researchers identified the hormone responsible for HG, a finding that upends old beliefs about HG’s causes and treatment.

HG should be taken more seriously than it is, according to researcher Marlena Fejzo, who was the lead author of the study, published in the journal Nature, which found that a hormone called growth and differentiation factor 15 (GDF15) contributes to HG.

What Is HG?

HG, from which Kate, Britain’s Duchess of Cambridge, famously suffered during her pregnancies, is essentially constant nausea and vomiting, a more severe form of the “morning sickness” that many women may experience in early pregnancy. While approximately 70 percent of pregnant women experience some nausea and vomiting, HG may affect between .3 percent and 10.8 percent.

In a May opinion piece about her discovery in the journal Trends in Molecular Medicine, Ms. Fejzo cited research published in BMC Medicine showing that beyond causing malnutrition in mothers, HG can result in serious health problems for their babies, including “abnormal brain growth, neurodevelopmental delay, autism spectrum disorder, childhood cancer, and respiratory disorders.”

Women with HG may have lower levels of the nausea-and-vomiting hormone GDF15 in their blood before pregnancy, and that can make them hypersensitive to it when it rises rapidly during pregnancy, Ms. Fejzo told The Epoch Times.

This contradicts the previous belief that a different hormone, human chorionic gonadotropin (hCG), was the culprit.

Ms. Fejzo has a doctorate in genetics and is a clinical assistant professor of population and public health sciences in the Center for Genetic Epidemiology at the Keck School of Medicine, University of Southern California. She is also a science advisor for and board member of the Hyperemesis Education and Research Foundation.

In an interview with The Epoch Times, Ms. Fejzo emphasized the importance of her findings to the treatment of pregnant women with HG and addressed three myths about the condition.

Myth 1

The Hormone hCG or the Psychological Stress of Pregnancy Causes HG

If people continue to believe the myth that hCG causes HG or is psychosomatic, Ms. Fejzo said, “researchers will continue to waste time and resources on measuring hCG levels and psychological factors.” Instead, she said, doctors and researchers need to “switch gears and move forward with the irrefutable evidence that the nausea and vomiting hormone GDF15 is strongly associated with HG.”

She called the idea that HG is psychosomatic (that is, a psychological response to the stress of pregnancy) a “misogynistic theory” and noted that it is still taught in medical schools today.

Myth 2

Severe Morning Sickness Is Harmless

“Many people think HG is self-limiting,” Ms. Fejzo told The Epoch Times, “and don’t know about the recent large studies [...] that show a significant association between HG and increased risk of adverse maternal, fetal, and child outcomes.”

She cited as an example the BMC study showing children whose mothers had had HG have smaller brains on average at age 10 than children whose mothers had not had HG.

The misunderstanding that HG is unpleasant but harmless “leaves patients at risk for being dismissed and undertreated,” Ms. Fejzo explained. Some patients may literally starve for weeks or months during pregnancy, she said. “If people continue to believe that HG is not associated with poor outcomes, despite strong evidence to the contrary, then they will continue to take it less seriously.”

Myth 3

Severe Morning Sickness Occurs Only in Humans

Another myth surrounding HG that also contributes to its undertreatment, said Ms. Fejzo, is the belief that it occurs only in humans. “Many animals exhibit a similar condition, and [in] some it can be even more extreme, like the maternal octopus who literally starves to death during gestation,” she told The Epoch Times.

This mistaken belief contributes to doctors “blaming” pregnant women and labeling HG a psychosomatic rather than a biological condition. Ms. Fejzo theorizes that morning sickness likely gave pregnant women a survival advantage in the days when scavenging for food was fraught with dangers.

Back when humans were hunter-gatherers, she pointed out, venturing out to search for food could have been extremely dangerous. “There was risk of injury, infection, eating something poisonous, getting caught in a storm, or getting eaten by a predator,” she said. “So it may have been that the less we put ourselves in harm’s way, especially very early in pregnancy when the nutritional demands of the fetus were lower, the more likely the mother and baby survived.”

While in most parts of the world, such dangers no longer lurk, and most of us are able to safely shop for food at grocery stores, this antiquated evolutionary survival mechanism lingers, she said.

Dispelling the Myths: ‘Full Steam Ahead’

Ms. Fejzo is hopeful that her research into GDF15 will soon translate to better treatment for HG, and she is hard at work to make this happen. 

“It is full steam ahead,” she told The Epoch Times. She is now the chief scientific officer of Harmonia Healthcare, a new clinic in Red Bank, New Jersey, dedicated to treating women with HG and setting up the infrastructure for more research and clinical trials. Similar clinics will open in the coming months in Philadelphia and New York.

Ms. Fejzo also hopes to secure funding for a trial to increase pre-pregnancy GDF15 levels in patients at high risk for HG in order to desensitize them to it, similar to the way people are desensitized to allergens, she told The Epoch Times.

Finally, she is working with the company NGM Bio, which plans to initiate a phase 2 proof-of-concept study of NGM120, a drug that blocks GDF15 signaling in patients with HG, by the end of this year.