As the uterus grows theres less and less room for the lungs which is why pregnant women often feel out of breath. Ad the fetus grows, pregnant women also need extra oxygen and blood. Heart is already working for two but because of the virus, the stress on the heart can cause inflammation. Finally, pregnant women’s blood has an increased tendency to clot, thought to be due to their need to quickly staunch bleeding after delivering a baby.. “COVID is thought to increase your likelihood of clotting, and then pregnancy further increases your likelihood of clotting,”