Pregnancy results in many physical changes. Apart from changes in weight and shape of your body, other alterations in your body chemistry and function happen. The heart has to work harder, your body temperature also increases slightly, body secretions increase, joints and ligaments are more flexible and hormones are changed.
Emotional or mood changes are also common because of hormonal changes and fatigue together with normal anxiety over sexuality, body image, impending motherhood, marriage and a lot more.
Below picture shows the normal discomforts of pregnancy, causes and possible relief measures: