[572] Now at that time the bhikkhunīs of the group of six wore a waist-string (kaṭisuttaka) at all times. People looked down upon them, criticized, and spread it about, saying, "… just like householder women who enjoy sensual pleasures." They reported this matter to the Blessed One. "Bhikkhus, a bhikkhunī should not wear a waist-string at all times; whoever should wear one commits an offense of wrongdoing (dukkaṭa). I allow, bhikkhus, a waist-string for one who is menstruating."
The Second Recitation Section (dutiyabhāṇavāra).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.