Purity: Order of Washing for Medium and Excessive Istiḥāḍah
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 396:
A woman who has medium istiḥāḍah and must perform wuḍūʾ as well as ghusl, must, based on obligatory precaution, first perform ghusl and then perform wuḍūʾ. However, if a woman who has excessive istiḥāḍah wants to perform wuḍūʾ, she must perform it before she performs ghusl.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)