It has been usually seen that pregnant woman mood tends to swing every now and then. This is a natural phenomenon as she has to go through many stages of pregnancy. At her first trimester she is usually found irritated as it is the beginning period and she is not used to carry the grown belly. SO it is bit frustrating for her. In the second trimester she tries to buck up the months and stretch it more. She remains normal and busy in her work. But while coming to her third trimester she usually feels a burden of the over grown belly and stretched nerves. She could not even move properly, lack of sleep and other physical issues make her sick and frustrated again. So the mood keeps on swinging time and often during pregnancy.