Researchers have found a link between increased levels of a hormone and nausea during pregnancy (including morning sickness). The results published in the journal Nature shed light on these complex metabolic processes and offer potential avenues for treatment going forward.
The majority of pregnancies (70%) are affected by nausea and vomiting, which can progress to a severe form known as hyperemesis gravidarum (HG). The hormone growth differentiation factor 15 (GDF15) has previously been implicated in morning sickness in previous literature; however, the underlying mechanism has yet to be described.
Dr. Stephen O’Rahilly from the University of Cambridge and others measured levels of GDF15 in expectant mothers in their first trimester and found a notable link between elevated levels of GDF15 and reported nausea and vomiting (including hyperemesis gravidarum). Further analysis of placental and maternal samples revealed that the foetus is responsible for the vast majority of the hormone circulating in the maternal plasma. The authors also found that lower levels of GDF15 prior to pregnancy are associated with a higher risk of developing hyperemesis gravidarum. Conversely, women with beta-thalassaemia (a condition in which GDF15 levels are chronically high) rarely reported nausea and vomiting in pregnancy. These results suggest that those with lower levels of GDF15 before pregnancy may be more sensitive to the increased levels of the hormone during pregnancy, and thus more affected by the sickness that it triggers.
“Our findings support a putative causal role for foetally-derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of hyperemesis gravidarum,” they write.
These findings suggest there may be a causal relationship between foetally-derived GDF15 and the risk of hyperemesis gravidarum: those who have lower initial levels of the hormone are more likely to experience sickness as the levels rise during the first trimester. “What makes the study a major advance is that it goes beyond establishing a correlation between GDF15 and nausea and vomiting in pregnancy, and provides genetic evidence for a potential causal mechanism,” notes an accompanying News & Views.
