A Muslim should hasten to remove impurity from himself or herself as soon as possible, since this will make permissible for him or her many things that would be impermissible if he or she is still in a state of impurity.
In the case at hand, a menstruating or confined Muslim woman is permitted to recite the Qur’an; if she has extra impurity through janabah (i.e., major ritual impurity due to a sexual discharge), she will not be able to perform some permissible acts of worship during menses, such as reciting the Qur’an, unless she removes this additional impurity.
Dr. Salah Al-Sawy, secretary-general of the Assembly of Muslim Jurists in America (AMJA), stated,
If a menstruating woman sees in her sleep that which requires ghusl, namely a wet dream, she should perform ghusl, as a means of lessening the impurity.
This becomes obligatory on her in case she would like to recite the Qur’an, since a woman during menstruation period can recite the Qur’an without touching the mushaf (i.e., an Arabic copy of the Qur’an), according to the correct of the opinions of scholars.
thus, she must perform ghusl from the janabah, as she can remove the janabah by ghusl but cannot stop menstruation.