Bukhari

Hadith Commentary:
➊
There are three types of circumambulation (tawaf):
©.
Tawaf al-Qudum:
It is also called the Tawaf of Greeting (tahiyyah).
This tawaf is performed immediately upon entering the House of Allah (Baytullah).
If a woman arrives in Makkah in a state of menstruation (hayd), this tawaf is waived for her.
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Tawaf al-Ifadah:
It is also called the Tawaf of Visitation (ziyarah).
This is a pillar (rukn) of Hajj.
This tawaf is performed on the 10th of Dhul-Hijjah.
It is never waived under any circumstance.
If a woman begins menstruating, she should wait until it ends, perform Tawaf al-Ifadah, and then return to her homeland.
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Tawaf al-Wada‘:
It is also called the Tawaf of Departure (sadr), which is performed at the time of returning home.
If a woman is in a state of menstruation, Tawaf al-Wada‘ is also waived for her.
➋
The purpose of Imam al-Bukhari rahimahullah is that after performing Tawaf al-Ifadah, which is a pillar of Hajj, if a woman begins menstruating, it is not necessary for her to remain in Makkah for Tawaf al-Wada‘; she may return to her home, because the Shari‘ah has waived it for her.
Tawaf al-Ifadah is also called Tawaf al-Rukn, Tawaf al-Ziyarah, and Tawaf Yawm al-Nahr.
The initial fatwa of Ibn ‘Umar radi Allahu anhu was that a menstruating woman must wait for purification (taharah) in order to perform Tawaf al-Wada‘.
When he learned that the Messenger of Allah sallallahu alayhi wa sallam had granted a concession in this matter, he retracted this position—or perhaps he had known of the concession earlier but had forgotten, and thus issued a fatwa contrary to it, but later, upon being reminded, he withdrew his fatwa.
From this hadith, it is understood that a menstruating woman cannot perform the circumambulation (tawaf) of the House of Allah (Baytullah).
(Fath al-Bari: 1/555)

1:
In the narration of Bukhari and Muslim, it is stated: "Ahlī bil-ḥajj wa iṣnaʿī mā yaṣnaʿu al-ḥājj ghayra annā lā taṭūfī bil-bayt," meaning: Proclaim the talbiyah for Hajj and do all the actions that a pilgrim does, except that you should not perform the circumambulation (ṭawāf) of the House (Ka'bah).

1744. Commentary:
➊ Women experiencing menstruation (hayd) or postnatal bleeding (nifas) should perform ritual bath (ghusl), enter into the state of ihram for Hajj or Umrah, recite the talbiyah, and remain engaged in tasbihat, seeking forgiveness (istighfar), and other remembrances (adhkar). Other than the circumambulation (tawaf) of the House of Allah (Baytullah), there is no other restriction upon them.
➋ Similarly, if someone experiences a wet dream (ihtilam), there is no defect in his ihram.