It is commonly thought that a pregnant woman's immunity is suppressed. In pregnancy, there is modification of the immune system to prevent rejection of the fetus and placenta. It is thought that the cell mediated immunity is modified by an increased in the production of T-helper cells as opposed to T-killer cells to reduce the risk of rejection. There appears to be a tendency towards humoral immunity. As the virus replicates intracellularly, the ability to fight off an infection is reduced. It is known that infections such as chicken pox get worse in pregnancy, particularly in the later half of pregnancy, but this is due to the risk of pneumonitis from local spread to the respiratory system of the virus and also the mechanical effects of the enlarged uterus on the diaphragm and the respiratory system. There is no evidence that Human Immunodeficiency Virus (HIV) or tuberculosis get worse in pregnancy. Hence, there is no evidence to suggest that pregnant women are at increased susceptibility of catching the flu virus [13] .