Cause of morning sickness, hyperemesis gravidarum discovered: study

For the millions of women worldwide who have endured morning sickness during their pregnancy, this news couldn’t come soon enough.

Medical researchers believe they’ve now discovered the cause of morning sickness, including hyperemesis gravidarum — nausea and vomiting so severe that it requires hospitalization, putting the health of the mother and her baby in danger of dehydration and malnutrition.

Recent headlines have brought attention to the somewhat rare but debilitating illness: Princess Kate Middleton was hospitalized with the condition during her pregnancies with Prince George, Princess Charlotte and Prince Louis. And comic Amy Schumer endured a bout of hyperemesis gravidarum during her 2019 pregnancy and was forced to cancel some tour dates.

Researchers hope their discovery will soon lead to a cure for the condition, which affects up to 3% of pregnancies, according to the Cleveland Clinic, and end the misery of morning sickness for the roughly 80% of women who’ve lived with it.

When does morning sickness begin?

It’s common for people who become pregnant to experience nausea as well as vomiting from around 4 and 18 weeks after conception. For some, however, the symptoms can continue for the full 9 months of pregnancy, and a small subset will be diagnosed with full-blown hyperemesis gravidarum. Symptoms of the latter condition can be so severe that sufferers risk losing more than 5% of their body weight in early pregnancy, according to the National Library of Medicine.

“Most women who become pregnant will experience nausea and sickness at some point, and while this is not pleasant, for some women it can be much worse — they’ll become so sick they require treatment and even hospitalization,” Professor Sir Stephen O’Rahilly of the University of Cambridge, who led the research, said in a news release.

Why does pregnancy cause morning sickness?

The culprit behind morning sickness is a hormone produced by the fetus known as GDF15. How sick the mother feels depends on how much of the hormone is produced by the fetus, and how much exposure to this hormone the woman had before her pregnancy.

“The baby growing in the womb is producing a hormone at levels the mother is not used to. The more sensitive she is to this hormone, the sicker she will become,” said O’Rahilly.

“Knowing this gives us a clue as to how we might prevent this from happening. It also makes us more confident that preventing GDF15 from accessing its highly specific receptor in the mother’s brain will ultimately form the basis for an effective and safe way of treating this disorder,” he added.

What are the new and best remedies for morning sickness?

Based on preliminary experiments with mice, the researchers believe that building up a woman’s tolerance to the hormone before pregnancy could hold the key to preventing sickness.

To alleviate symptoms, the National Library of Medicine recommends various lifestyle changes. Many factors can trigger nausea, such as certain foods, textures and smells, blinking lights or portion — and should be avoided. Pregnant people with morning sickness must drink plenty of fluids and should attempt to eat at any point they feel well enough — as further hunger and dehydration will only put further stress on the body.

Some studies have shown that supplements of vitamin B6, doxylamine (Unisom) and ginger can have a soothing effect on people with morning sickness, who are advised to discuss the treatment with their doctor before trying.

“When I was pregnant, I became so ill that I could barely move without being sick. When I tried to find out why, I realized how little was known about my condition, despite pregnancy nausea being very common,” said Dr. Marlena Fejzo of the University of Southern California, co-author of the study, published today in Nature.

“Hopefully, now that we understand the cause of hyperemesis gravidarum, we’re a step closer to developing effective treatments to stop other mothers going through what I and many other women have experienced.”