Every year, pre-eclampsia kills tens of thousands of mothers and babies — and the tragedy is that it often isn't caught until it's already dangerous.
The condition, which typically strikes in the second half of pregnancy with sudden surges in blood pressure, affects around **one in twenty pregnancies worldwide**. It is the **second most common killer of mothers globally**. And for most of medical history, the first real warning a woman received was the symptom itself — by which point the condition had already taken hold.
A study published in *Genome Biology* may have found a way to change that — using molecular signals hidden in DNA that is, in a sense, millions of years old.
**The Hidden Signals in Our Ancient DNA**
About 8% of the human genome is made up of **retroviral remnants** — genetic material left behind by viruses that infected our ancestors millions of years ago and were gradually incorporated into our DNA. For most of scientific history, these sequences were dismissed as "junk." Over the past two decades, researchers have discovered that many of these ancient viral insertions play active roles in regulating genes — acting as switches that turn genes on or off in specific tissues and circumstances.
The new study, led by **Dr Manvendra Singh** (INEM and Institut Imagine, Paris) with collaborators from the **Max Delbrück Center**, **Cornell University**, and the **University of Bath's Milner Centre for Evolution**, found that two specific retroviral remnants — **LTR8B** and **MER65** — act as regulators of a gene called **PSG9**, which produces a protein critical for healthy placental development.
When this regulatory system works correctly, the placenta forms properly and the pregnancy progresses normally. When it malfunctions — when LTR8B fails to switch on PSG9 at the right time — the placenta cannot embed itself properly in the uterine wall. That failure is the hallmark event of **Early-Onset Pre-eclampsia (EO-PE)**: the most dangerous form of the condition.
**What Makes This a Breakthrough**
The key discovery is that when this molecular switch fails, it leaves measurable traces — detectable in the **mother's blood from early in pregnancy**, weeks before blood pressure begins to rise.
"Pre-eclampsia is both remarkably common and potentially lethal," said **Professor Laurence Hurst** at the University of Bath, a co-corresponding author. "It is the second most common killer of mothers globally, making it both an evolutionary conundrum and a serious maternal and neonate health problem. Unfortunately, pre-eclampsia is often recognised too late — when a pregnant woman's blood pressure is already dangerously very high."
The researchers are now pointing toward a **non-invasive blood test** that could screen for these early markers during routine early-pregnancy check-ups — identifying women at elevated risk weeks before any symptoms appear.
"This work shows that an ancient viral sequence can act like a manual for a placental gene," said Dr Singh. "By mapping the regulatory region and testing it functionally, we have now connected genome evolution to a concrete disease mechanism — and to the possibility of earlier detection."
**What Earlier Detection Could Mean**
Pre-eclampsia has no cure except delivery — but catching it early dramatically changes what can be done. Women identified as high-risk early can be:
💊 Given **low-dose aspirin** from early in pregnancy, which reduces the risk of developing severe pre-eclampsia by up to 60% 🏥 Monitored more closely, with earlier hospital admission when needed 🩺 Given **magnesium sulphate** to prevent seizures (eclampsia) if blood pressure rises 👶 Managed for delivery timing to protect both mother and baby
The gap between "we don't know she's at risk" and "she's at risk and we've been managing it for three months" is the gap between outcomes that are preventable and outcomes that aren't.
**The Evolutionary Angle**
There's something almost philosophical about the finding: a disease that kills modern mothers can now potentially be detected using molecular fingerprints left by viruses that infected our ancestors before *Homo sapiens* existed as a species.
The ancient DNA that once seemed like biological noise is, in fact, part of the conversation the placenta has with the body — a conversation that goes wrong in pre-eclampsia, and one that scientists can now, for the first time, begin to overhear.
*Sources: University of Bath (March 2026) · Genome Biology (Springer Nature) · Max Delbrück Center · Institut Imagine · Cornell University*
