Scientists have identified the hormone that causes morning sickness in pregnant women.
The mystery behind morning sickness – characterized as nausea and vomiting in the first trimester of pregnancy – has been solved by scientists who recently discovered the specific hormone after studying severe cases of the body's reaction.
A study recently published in Nature scientific magazine said the culprit was the hormone GDF15. O University of Cambridge said the hormone is produced by the placenta and also by other tissues outside of pregnancy. In another study by National Institute of Health, the hormone was associated with causing nausea and vomiting, scientifically called emesis.
Despite being called morning sickness, nausea and vomiting can occur at any time, but according to the Mayo Clinic, they can also progress to hyperemesis gravidarum. Some symptoms of this severe form of morning sickness can result in weight loss and dehydration. The condition reportedly affects up to three percent of pregnant people and can cause a pregnancy to be classified as “high risk.”
Dr. Marlena Fejzo – a geneticist at the University of Southern California Keck School of Medicine and co-author of the new study – explained to The New York Times that severe cases of morning sickness are not taken seriously in the medical field. She said: “I’ve been working on this for 20 years and there are still reports of women dying from it and women being mistreated.”
She added to the outlet that she was interested in finding out what causes hyperemesis gravidarum because of her experience with morning sickness. At the time, the nausea and vomiting were so severe that she miscarried.
Dr. Fejzo and fellow scientists at the University of Cambridge checked the presence of the hormone in the blood of pregnant women and identified whether or not the women had genetic risk factors for hyperemesis. Through their research, they discovered that those who experienced hyperemesis had significantly higher levels of GDF15 during pregnancy compared to those without symptoms, confirming that the hormone may be the cause of hyperemesis.
However, researchers have also found that the presence of the hormone can affect pregnant women differently, as seen in a group of women in Sri Lanka with a rare blood disorder that caused chronically high levels of the hormone. Despite the overwhelming amounts of GDF15, women rarely experienced morning sickness.
Regarding the results in Sri Lankan women, Dr. Stephen O'Rahilly – an endochronologist at the University of Cambridge who led the research – confirmed: “It completely eliminated all nausea. They have virtually no symptoms during pregnancy.
Dr. O'Rahilly theorized that a large amount of the hormone in the blood had a protective effect against hyperemesis, and they tested their hypothesis in rats by giving them small amounts of the hormone. When they reportedly gave the mice a small amount of the dose at first, their appetites were negatively affected. However, after giving them a higher dose of the hormone three days later, they noticed that the mice were more insensitive to its effects.
The scientists said they hope their research could lead to the creation of drugs that treat hyperemesis and that are also safe for pregnant women. Until now, this type of medication is mainly prescribed to cancer patients.