All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Your wife is not obligated to do anything and her ‘Umrah is valid, Allaah willing, as long as she is not certain that she offered Tawaaf while she was menstruating. That is because if something is possible to occur in one of two times, then it should be attributed to the nearest of them. (The general rule is attributing an incident to the most recent time, i.e. to the time closest to the present. That is because the existence of the incident in the closer time is agreed upon, while the later time is doubtful).
Based on that, since it is possible that such blood may have occurred in Tawaaf or after it, then it should be assumed to have occurred at the latest of the two times and thus her Tawaaf is valid. For more benefit, please refer to Fatwa 152643.
Allaah Knows best.