 When Carrie has her first menstrual cycle at the age of 16, Margaret refers to it as the 'Curse of Blood' and claims that it was brought on by some sort of sexual sin on Carrie's part.After berating Carrie, Margaret locks her in the "prayer closet" until it is time for bed.When Carrie is asked to the prom by Tommy Ross, Margaret initially forbids it, but Carrie insists on this last opportunity to fit in and rei°nforces her demand with her telekinetic power.