Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh

 

Yes as the Imam said, when one divorces his wife while she is in her period it is called the innovative divorce which does not match the proper way the prophet (peace be upon him) advised us to follow in case we really mean to end marriage.

 

And for that if you divorced your wife during her menstrual period, the divorce in not applicable and she is still your wife with nothing needs to be done.

 

Almighty Allah knows best.