Flu can be life-threatening for pregnant women and result in preterm delivery or miscarriage, study reveals

Influenza, popularly known as the flu, is one of the most common respiratory infections experienced by people throughout the world, infecting 3 to 5 million people every year. In most cases, it gets cured on its own but sometimes it can turn into a severe life-threatening condition.In a recent study, published in the journal PNAS on 21st September 2020, it was revealed how influenza A virus infection in pregnant women can cause severe harm to both mothers and the unborn.Flu in pregnant womenThe Influenza virus does not transmit vertically from the mother to the baby via the placenta. However, it has been observed that the severe effects of influenza on pregnant women can harm the fetus. Previous studies have shown that pregnant women with influenza are at a higher risk of developing pneumonia and requiring hospitalisation. Also, these pregnant women bear a higher risk of miscarriage, preterm births or restricted growth of the fetus.So far, it was assumed that the flu may be a serious health problem for pregnant women because their immunity gets suppressed during the gestation period, making it hard for them to fight the infection.However, new research by the scientists of the University of Missouri, Columbia, states that the Influenza A virus has a different effect on pregnant and non-pregnant bodies, which makes it a serious health hazard during pregnancy.Influenza A in pregnant miceTo prove their theory, scientists performed the experiment on two groups of mice; pregnant mice at embryonic day 12 (equivalent to the second trimester of pregnancy in humans) and non-pregnant female mice. There were 6 to 8 mice in both groups.Both these groups were infected with a moderately pathogenic strain of Influenza A virus. The non-pregnant mice showed normal signs of the seasonal flu and their infection was limited to the lungs. However, in pregnant mice, there was an increased overall inflammation in the body, with increased neutrophils, lymphocytes and platelets in the blood.Results of the studyThe scientists found that Influenza A virus infection during pregnancy incites inflammation in the vasculature (blood vessels) of the body, which hampers blood circulation.After this inflammatory response in the body, the immune system sends innate immune cells and white blood cells to cope with the inflammation. There is also an excess production of inflammatory cytokines (such as Interleukin-1 beta and TNF alpha), inflammatory adhesion molecules and oxidative stress mediators in the blood vessels in response to Influenza A virus.This damage results in inflammation in the aorta, which is the main artery that carries blood away from the heart to the rest of the body.The scientists believe that more studies are needed to establish the effect of Influenza A virus in pregnant women in order to prevent cardiovascular damage in them.For more information, read our article on Flu (Influenza).Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.