Astanga Hrudaya
ईषत्कृष्णं विगन्धं च वायुर्योनिमुखान्नुदेत्। ततः पुष्पेक्षणादेव कल्याणध्यायिनी त्र्यहम्॥२३॥
during the rtu (menstrual period), is expelled out by vayu (vata), through the orifice of the yoni (uterus and vaginal tract) From the moment of appearance of the menstrual flow, for a period of three days, the woman should harbour only good thoughts, avoids bath and decorations,
english translation
ISatkRSNaM vigandhaM ca vAyuryonimukhAnnudet। tataH puSpekSaNAdeva kalyANadhyAyinI tryaham॥23॥
hk transliteration by Sanscript