Pregnancy Diet: Boost Your Immunity With Super Foods If you are pregnant, you need to take special care to boost your immunity with the right nutrients. Good circulation and blood flow to every tissue in the body allow the immune system to develop a strong defense against invading pathogens. Pregnancy is a period of increased metabolic demand because of changes in a woman’s physiology and the requirements of a growing fetus. Pregnancy alters the immune system. The design of a woman’s immune system is complex and it is influenced by diet, lifestyle, sleep, exercise, and stress levels. With the excitement of a baby along the way, people often begin to buckle their belts for the nine months of caution up ahead. While everything the mother-to-be does is under scrutiny, one of the first things that need attention is the pregnant woman’s diet. It is essential to have a diet that not only suits the mother through those nauseous mornings and sleepless nights but is also healthy for the baby.