The extreme form of nausea and vomiting during pregnancy is associated with ten genes, one of which is probably mainly responsible for this condition.
Most people experience some degree of nausea and vomiting during early pregnancy, but up to about 11% have symptoms so severe that they are no longer able to eat and drink, and may even require hospitalization.
According to , this condition is called hyperemesis gravidarum (HG) and can continue throughout the entire pregnancy, despite the fact that there are still no treatments approved by the North American regulator, the Food and Drug Administration (FDA).
In a new one, published last week in Nature Geneticsresearchers found evidence that the hormone growth differentiation factor 15 (GDF15) gene is the main cause of HG, which had already been suggested in other studies.
Scientists have also identified six additional genes associated with the condition, including one that could control production of the peptide-like glucagon-1 (GPL-1)a hormone involved in the regulation of insulin and appetite. This gene is also the largest known genetic risk factor for type 2 diabetes.
“This will be useful for exploring new therapeutic avenues and better ways to predict, diagnose, treat and potentially prevent HG in the future”, says the study’s first author, Marlena Fejzo.
The pregnancy hormone, human chorionic gonadotropin (hCG) has long been considered the underlying cause of HG, as its levels rise dramatically in early pregnancy. Estrogen has also been identified as a possible cause, as its levels also increase drastically.
In this new study, the team combined data from new ones independent studies on HG carried out in the USA and Europe. They compared the complete genomes and the autosomes, the chromosomes excluding the X and Y sex chromosomes, of almost 11 mil people with diagnosed HG and more than 420 mil people with a history of pregnancy but without HG.
Most of the data still came from individuals of European descent, and the data also included about 13 mil people of Asian descent, more than 1200 people of African descent and 75 people of Latin descent.
The team identified ten genes associated with a high risk of HG, with the gene being GDF15 the main indicator in all populations.
For the first time, researchers also identified an association with TCF7L2the main genetic risk factor for type 2 diabetes ea gestational diabetes. Previous studies have found that this gene can regulate GPL-1, the same hormone mimicked by drugs like Ozempic and Wegovy.
“The exact reason why learning and memory genes are linked is unclear, but it is thought that they may play a role in shaping the extreme food aversion responses seen in people with HG,” adds Fejzo.
Finally, the team of scientists intends to launch a clinical trial in the coming months. This will involve administering metformina diabetes drug that increases GDF15, to patients with a history of HG.
Patients taking part in the trial plan to have more children in the near future, so the trial will test whether metformin desensitizes them to GDF15 before conception. The goal is to reduce nausea and vomiting once you become pregnant.
