Study: Flu Can Be Devastating for Pregnant Women

New research from RMIT University helps explain why the flu can lead to life-threatening complications during pregnancy, suggesting that the virus does not stay in the lungs but instead spreads throughout the mother’s body.

The findings could additionally help researchers understand the fundamental biology of how coronavirus disease 2019 (COVID-19) spreads from the lungs to the body.

The research showed that during pregnancy, the flu spreads from the lungs through the blood vessels into the circulatory system, triggering a damaging hyperactive immune response, according to the study authors.

The study analyzed pregnant mice with the flu who had severe inflammation in the large blood vessels and the aorta. A healthy blood vessel dilates 90%-100% to let blood flow freely, whereas the flu-infected blood vessels functioned at only 20%-30% of capacity.

“We found a dramatic difference in these inflamed blood vessels, which can seriously affect how much blood makes it to the placenta and all the organs that help support the growing baby,” said researcher and associate professor Stavros Selemidis, PhD, in a press release. “We’ve known that flu infection in pregnancy results in an increased risk of babies being smaller and suffering oxygen starvation.”

Selemidis added that their research shows the critical role that the vascular system could be playing, with inflammation in the blood vessels reducing blood flow and nutrient transfer from the mom to the baby.

The research suggests that the influenza infection may tip that underlying inflammation in the mother’s body over the edge into a full-blown systemic inflammatory event. Further, the findings revealed a new connection to pre-eclampsia, a dangerous pregnancy complication characterized by high blood pressure.

“While it will take further research to unpack this link, it could mean drugs targeting vascular inflammation that are currently being tested could potentially be repurposed in future for flu infection in pregnancy,” Selemidis said.

Lead author Stella Liong, MD, said that this research also has implications for our understanding of how the COVID-19 virus may be affecting the vascular system.

“Flu and coronavirus are different, but there are parallels and we do know that COVID-19 causes vascular dysfunction, which can lead to strokes and other cardiovascular problems,” Liong said in a press release.

Liong added that the studies in pregnancy offer new insights into the fundamental biology of how respiratory viruses can drive dysfunction in the vascular system, being possible valuable knowledge for those scientists working directly on treatments and vaccines for COVID-19.

REFERENCE

New study reveals why flu can be devastating for pregnant women. RMIT University. https://www.rmit.edu.au/news/all-news/2020/sep/flu-pregnancy. Published September 22, 2020. Accessed September 29, 2020.