- 1 in 5 babies born to infected moms get the virus
- At-risk moms in tropical regions need urgent monitoring
- Not a treatment — but a critical warning for care
This study reveals when during pregnancy chikungunya poses the greatest danger — and it’s later than we thought.
Imagine being pregnant, living in a place where mosquitoes are everywhere. You get a fever, joint pain, a rash. It feels like a bad flu. But what you don’t know could hurt your baby. That’s the reality for thousands of women in tropical areas facing chikungunya virus.
Now, a major new analysis is changing how doctors see the risk — especially based on when during pregnancy a woman gets infected.
Chikungunya is a virus spread by mosquitoes. It’s common in parts of Africa, Asia, the Caribbean, and Latin America. Millions are exposed every year.
Most people get fever, pain, and rash. For many, it passes in days. But for pregnant women, it can be different.
Until now, we didn’t have a clear picture of how often the virus passes from mother to baby — or how bad the outcomes could be.
And with climate change, mosquitoes that carry chikungunya are spreading to new areas. More women are at risk.
Current prenatal care often doesn’t include chikungunya screening. Many cases go unnoticed. That could be dangerous.
The surprising shift
We used to think chikungunya was risky at any stage of pregnancy.
But this study shows something unexpected: timing is everything.
Infections in the first or second trimester rarely lead to the baby catching the virus. The risk is less than 4%.
But in the third trimester? That changes fast.
The risk jumps nearly 30-fold.
And if a woman is infected during labor, almost half of babies get the virus.
This is not a small difference. It’s a sharp, dangerous spike in danger — right at the end.
What scientists didn’t expect
Here’s the catch: most harm to babies doesn’t come from being born with the virus alone.
It’s what happens after.
Many newborns struggle to feed. Some have high fevers. Low platelets — that’s what thrombocytopenia means — can lead to bleeding.
And some face long-term issues. The study found an 11 times higher risk of delayed brain development.
That’s not just a number. It could mean delays in sitting up, talking, or learning.
Like a hidden switch
Think of the placenta like a border checkpoint.
Early in pregnancy, it blocks the virus — like a strict guard.
But near the end, the checkpoint weakens. Hormones shift. Blood flow changes.
The virus slips through.
And during delivery, when the baby passes through the birth canal, it can be exposed to infected blood or fluids.
That’s when the risk peaks.
It’s not just about the virus being present. It’s about when the body becomes vulnerable.
The data behind the findings
Researchers looked at 57 studies from around the world. More than 4,000 pregnant women with chikungunya were included.
They focused on real-world cases — not lab experiments.
The analysis combined results from Africa, the Americas, and Asia. This gives a global picture, not just one region.
The studies tracked what happened to moms and babies — from infection to birth and beyond.
One in five pregnant women with chikungunya passed the virus to their baby — overall.
But break it down by trimester, and the story changes.
First trimester: less than 4% transmission. Second trimester: just over 1%. Third trimester: 36.5%. During delivery: nearly half.
That’s a massive jump.
And adverse outcomes in babies? More than 1 in 3.
Most common: trouble feeding, fever, low platelets.
Neonatal death occurred in 7 out of every 100 infected babies — a rate far higher than average.
This doesn’t mean this treatment is available yet.
But there’s a catch.
Most of the data comes from areas with limited healthcare.
That means some cases may be worse due to delays in care — not just the virus itself.
Also, many studies didn’t track children past the first few weeks.
We don’t yet know how many with delayed development recover over time.
And while the link to long-term issues is strong, we need more research to confirm how often it happens.
Where this fits in
Experts say this study fills a critical gap.
We now have clear evidence that late-pregnancy infection is the highest risk period.
That changes how we should protect moms.
It supports adding chikungunya testing in the third trimester in high-risk areas.
And it calls for watching babies closely if mom was infected near delivery.
This isn’t about fear. It’s about focus.
If you’re pregnant and live in or travel to a region with chikungunya, talk to your doctor.
There’s no vaccine or specific drug yet.
But knowing your risk — especially in the third trimester — can help you take steps.
Use mosquito nets. Wear long sleeves. Eliminate standing water.
And if you get sick, insist on evaluation — even if symptoms seem mild.
Your timing could protect your baby.
Right now, this research is guiding public health plans — not changing clinics overnight.
More studies are needed to test screening programs and early interventions.
But the message is clear: protect pregnant women in the final months.
And prepare hospitals to monitor newborns when moms are infected.
With better awareness, we can reduce harm — one pregnancy at a time.