How serious is iron deficiency anemia?

Severity and cause. Will depend on how severe it is and whether you are pregnant or not. If you only have mild deficiency-you probably don't have any symptom. If severe enough, tired, fatigue, dizziness, chest pain, shortness of breath can be the symptoms. In pregnancy iron is very important for the fetus. It is crucial to know what is the cause. Bleeding? Malabsorption, cancer? Etc- this needs to be found out.