Pregnancy sickness isn’t just bad luck. It’s in your DNA.
For years doctors dismissed hyperemesis gravidarium (HG) as psychological or weak nerves. That ended with a massive international study published in Nature Genetics. The Keck School of Medicine at USC led the charge, finding nine more genes linked to HG. Six are brand new discoveries.
This isn’t mild nausea. HG affects roughly 2% of pregnancies. Women vomit relentlessly. Eating becomes a physical battle. The body starves. Dehydration sets in. Risks to the baby and mother skyrocket.
The previous big finding involved the GDF15 hormone. The new work builds on that foundation but looks wider.
Researchers analyzed DNA from over 10,000 women with HG. They compared them to 461,000 controls. Ancestries spanned Europe, Asia, Africa, and Latino groups. The scale was unprecedented.
“We’ve been able to tease out details previously unknown,” Marlena Fejzo explained. She is the clinical assistant professor who led the study. More participants meant clearer signals.
GDF15 remains the biggest villain here. The hormone spikes during pregnancy. Your genes determine how your body reacts.
Some women have mutations that keep them from seeing GDF15 often. Their systems aren’t used to it. When pregnancy hits, the shock is severe. Vomiting follows. Women genetically accustomed to higher levels fare better.
“The fact that we studied multiple ancestry groups suggests results apply broadly.”
That’s the other win here. Diversity matters.
Four genes were already on the map. GFRAL makes the receptor for the hormone. IGFBP7 and PGR help build the placenta. Standard fare so far.
Then came the new six.
One stands out: TCF7L2. It is a known risk factor for type 2 diabetes. It also ties into gestational diabetes. The connection makes sense. This gene likely interacts with GLP-1, a gut hormone managing blood sugar, appetite, and nausea.
A new target emerges.
Other genes point toward appetite control and brain plasticity. Your brain might literally learn to associate certain foods with sickness. It’s not just biology fighting itself. It’s neural pathways locking onto aversions.
Why does the brain change like that?
The study didn’t just find causes. It found complications. Some HG-linked genes tied to shorter pregnancies and preeclampsia. A dangerous loop of conditions.
Treatment options are… meh right now. Zofran works for maybe half the people. Partial relief doesn’t cut it when you’re starving.
Here’s where it gets interesting.
Fejzo’s team is testing Metformin. A common diabetes drug. It raises GDF15 levels naturally.
The theory? Take it before getting pregnant. Desensitize your body. Teach the system to ignore the hormone spike. Prevent the sickness entirely.
It’s a preventative strike against nausea.
We don’t have the answers yet. Clinical trials will take time. But the path is clearer now. We’re not just treating symptoms. We’re looking at the wiring underneath.
Maybe we finally stop blaming psychology for what is purely biology.
“Now we can dig deeper into new possible pathways for treatment.”
The work is done. The waiting game starts now.
Reference: Fejzo M, et al. Multi-ancestry genome-wide association… Nature Genetics. April 2024. [1]
