Assalamu Alaikum wa rahmatULLAHI wa barakatuHU,

Can a menstruating woman perform I'tikaaf? And can a person's I'tikaaf begin from sometime in the middle of Ramazan, if he/she chooses not to sit for I'tikaaf for the entire month?

JazakumULLAH Khair,
Wassalam ma'al-ikram