Question: Is it permissible for a woman on her menses to sit in the mas’aa?
Response: Yes, it is permissible for the woman on her menses to sit in the mas’aa, because the mas’aa is not considered (part of) al-Masjid al-Haraam. In that case, if the woman’s menses started after the tawaaf and before the sa’ee, then she (is permitted) to do the sa’ee because thesa’ee is not the tawaaf. Also, (to be in the state of) purity is not a condition. So, based upon this, we say that if the woman on her menses was to sit in the mas’aa waiting for her husband (family), then there is no harm in her doing this.
Shaykh Ibn ‘Uthaymeen
Fataawa al-Hajj wal-‘Umrah waz-Ziyaarah – Page 69.fatwaonline.com