Two days ago my wife fainted, never has before. she had blood tests, low hemoglobin, but she has been very forgetful and tired since. is that normal?

Call doctor.: If her hemoglobin is so low that she is fainting, get seen right away.Low hemoglobin can be due to blood loss or to other serious problems and if her symptoms are getting worse that is very troubling. If you did not tell your doc about the fainting (if she was told she was anemic before that) call your doc now or go to the ER. Something has changed or worsened. No driving if weak and dizzy!

Anemia: Significant anemia can cause the symptoms you described. Additionally low thyroid function can cause severe fatigue, difficulty thinking etc. She should check with her physician about testing. All the best.

Not normal: Low hemoglobin can cause someone to faint, but there are many other causes. When anemia develops slowly over time, it rarely causes fainting unless the hemoglobin is extremely low. Sudden drop in hemoglobin which occurs with loss of a fair amount of blood is more likely to cause fainting. Being tired is the common symptom of anemia. Have other causes of your wife fainting been ruled out?