Getting her menses while she is in the masjid

Question: A woman had blood starting to flow while she was in the Masjid of the Prophet (sal-Allaahu ‘alayhe wa sallam). She stayed in the masjid for a little while until her husband had finished the prayer and she could leave with him. Did she commit a sin?

Response: If she was not able to depart from the masjid by herself, then there is no harm in what she did. However, if she was able to leave by herself, it is obligatory upon her to exit as quickly as possible. This is because the menstruating woman, post-partum bleeding woman and sexually defiled person are not allowed to sit in the masaajid (plural of masjid). This is based on Allaah's statement, "Nor while sexually defiled except when traveling on a road" (an-Nisaa. 43). It is also narrated from the Prophet (sal-Allaahu ‘alayhe wa sallam) that he said, "I do not permit the menstruating woman or the sexually defiled person to enter the masjid.

Shaykh Ibn Baaz
Fataawa al-Mar.ah