The first part of this Shloka is an extension of previous Shlokas in that it is there for the protection of their Brahmcharya. The second part of the Shloka explains: Vratopavasauha Kartavyo Muhurdeha Dharmastatha - They should constantly control their body through observance of frequent fasts and Vratas. Therefore they should observe Ekadashi Upavas as well as other Vratas such as Dharana Parana. Similarly they should perform such Vrata-Upavas as Prayaschit if they were to accidentally touch some other man. They should thus constantly perform these rituals in order to maintain control over their body.
Nirnyasindhu of Skanda Purana explains, ‘Vidhvas should not wear their hair in an Amboro (knot or platted hair at the back of the head) as it is a sign of binding to one’s husband. Thus they should shave their head, keep their hair in the form of a Jatta or keep their hair without performing Sanskars. They should eat only once a day and observe frequent fasts for a month or observe the Vrata of Chandrayana. If she sleeps upon a bed then she condemns her husband to hell. She should not bathe with rich oils nor wear perfumes. She should not sit on an ox, wear a corset nor adorn herself with clothing and ornaments that are unacceptable in society.’
‘She should observe additional Vratas and Niyamas during the months of Vaisakh, Kartika and Magh. During Chaturmaas and Adhikamaas, women should observe additional Vrata-Niyamas.’
Note, earlier in this quote from Nirnyasindhu - it stated the fact that a married woman should wear her hair in an Amboro as it represents her marriage and binding to her husband. It is for this reason that it is sometimes shunned in society for married women to cut their hair or wear her hair open (untied).