Is she spotting or bleeding lightly, or is she having a normal period?
It's not abnormal for a woman to spot or bleed very lightly in early pregnancy as the embryo implants itself into the uterus. However, if your wife is bleeding bright red, heavily, or with clots (like a normal period) then she probably has had a chemical pregnancy.
Chemical pregnancies are basically very early miscarriages. Most women have them and don't even know it. They usually just think their periods are a little late.
If your wife has had a chemical pregnancy then I'm very sorry.