Wife Is Pregnant And Work Won’t Let Her On Light Duty

Me and my wife work in the same job and it is physically demanding job. After our appointment today, we got a note from her doctor saying she needs to go on light duty at work for pregnancy. This will be fine this time, but my job has a rule where you can’t go on light duty for the same reason in a rolling calendar year. My question is, if my wife has a note from the doctor specifically saying she needs to be on light duty for pregnancy and they deny because of said rule earlier in post, can I do anything legally?

Edit: I forgot to mention light duty only last 3 months at a time