If you've experienced Hyperemesis Gravidarum, you've probably asked the question I asked too:
Why is this happening to me?
For a long time, the answer to what causes severe Pregnancy Sickness was frustratingly unclear.
Research is changing that.
Scientists are learning much more about the biology behind nausea and vomiting in pregnancy and Hyperemesis Gravidarum (HG), including the role of hormones and genetics.
We still don't have every answer. But HG is increasingly being understood as a biological condition - and that's important.
First, what is Hyperemesis Gravidarum?
Hyperemesis Gravidarum is the severe end of nausea and vomiting in pregnancy.
According to the Royal College of Obstetricians and Gynaecologists (RCOG), HG can interfere with quality of life and with a woman's ability to eat and drink normally.
It's very different from the image many of us have of feeling a little queasy in the morning.
Anyone who has lived through HG knows that.
So what causes HG?
There isn't one simple answer.
Pregnancy involves enormous biological changes, and researchers are still investigating why some women experience relatively little nausea while others become severely unwell.
One of the most important areas of research in recent years has centered on a hormone called GDF15.
What is GDF15?
GDF15 - growth differentiation factor 15 - is a hormone.
During pregnancy, the placenta produces GDF15, and research has linked the hormone with appetite and nausea.
RCOG's current patient information explains that genetic differences may contribute to some women experiencing worse Pregnancy Sickness through differences involving GDF15.
This doesn't mean researchers have found one simple “HG gene” or that GDF15 explains every woman's experience.
But it has given scientists an important biological pathway to investigate.
What does genetics have to do with HG?
Researchers have also identified genetic associations with Hyperemesis Gravidarum.
That matters because it adds to a growing body of evidence that there are biological reasons why susceptibility to severe Pregnancy Sickness differs between women.
Genetic association does not mean destiny.
Having a particular genetic variant doesn't automatically mean someone will develop HG, and genetics alone cannot currently tell an individual woman exactly what her pregnancy will look like.
Instead, these findings are helping researchers piece together the biological mechanisms involved.
Why does this research matter?
For those who have experienced HG, there is something significant about seeing the condition investigated at this level.
Pregnancy Sickness has historically been surrounded by misconceptions and minimisation.
Better understanding of its biology can help move the conversation away from the idea that severe sickness is simply something women should expect to endure during pregnancy.
It can also give researchers clearer biological pathways to investigate when developing and evaluating future approaches to prevention and treatment.
But that's future-facing.
Research into a mechanism is not the same thing as having a new treatment available today.
Do we know everything about HG now?
No.
Science rarely moves from “we don't know” to one definitive answer overnight.
Research into GDF15, genetics and other biological mechanisms is continuing, and new studies need to be considered alongside the wider body of evidence.
That's why we're cautious about headlines suggesting scientists have simply “found the cause of morning sickness”.
The emerging science is far more interesting - and more complicated - than that.
What does this mean if I'm experiencing HG now?
The research may help explain more about why HG happens, but it doesn't replace clinical care.
If you're experiencing severe nausea or vomiting, struggling to eat or drink, losing weight, becoming dehydrated or finding that Pregnancy Sickness is significantly affecting your daily life, speak to your GP, midwife or maternity team.
There are recognised treatment pathways for nausea and vomiting in pregnancy and HG.
And if you're struggling to navigate those conversations, Pregnancy Sickness Support provides specialist information and support for women and families affected by Pregnancy Sickness and HG.
From lived experience to better understanding
When I experienced HG, I wasn't thinking about hormones, genes or biological pathways.
I just wanted to know why I was so ill.
That's partly why I find this area of research so interesting now.
We still don't have all the answers. But the scientific understanding of Pregnancy Sickness and HG is moving forward - and we'll continue following that research as it develops.
Medical disclaimer: This article is for general information only and does not constitute medical advice. If you are concerned about symptoms during pregnancy, please speak to an appropriate healthcare professional.
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