Researchers have discovered why influenza can lead to life-threatening complications during pregnancy. In most people, influenza stays in the upper respiratory tract – mainly the nose – and clears without spreading further. But during pregnancy, the virus can extend beyond the lungs into the cardiovascular system, increasing the risk of severe complications for mothers and babies.
A new preclinical study using animal models was published recently and reveals precisely why the virus can spill into the bloodstream during pregnancy, opening the door for targeted treatment. The study is a bilateral partnership between Trinity College Dublin, with collaborators from RMIT University and the University of Adelaide and is published in Science Advances.
Researchers identified a viral sensor in the immune system, known as TLR7, that can become overactive during pregnancy, amplifying inflammation and spreading disease into the bloodstream.
Blocking TLR7 could help prevent the harmful inflammation that makes flu in pregnancy so dangerous. This work can help protect developing babies by stopping the placenta from becoming overly inflamed during flu infection.
Prof John O’Leary, School of Medicine, Trinity College Dublin, said: “This international research is of high impact in relation to our understanding of viruses and pregnancy and the role of the maternal immune response.”
Earlier studies from RMIT have shown that severe flu in pregnancy can have longterm impacts on babies’ brain development, by inflaming blood vessels and reducing the flow of oxygen and nutrients from mother to baby.
Regarding research impact, this new study pinpoints the underlying cause of that damage, reshaping our understanding of flurelated risk in pregnancy and opening the door to more targeted therapies.
RMIT co-lead author Professor Stavros Selemidis said future treatments could focus on the immune system rather than the virus itself. “Our study shows that in pregnancy, the problem isn’t just the flu virus – it’s the immune system overreacting. That’s where future treatments could really make a difference.
“We’re ready to work with partners to help develop the next generation of therapies and clinical guidelines.”
