Sunan Abu Dawud
277
Sahih+3

This tradition has been transmitted through the chain of narrators like that of al-Laith to the same effect. It says; She should abandon prayer considering that period (she used to menstruate). When the time of prayer approaches, she should take a bath, tie a cloth over her private parts and offer prayer

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid