Iddah is a waiting period. Its duration is usually (a) until she gives
birth if she is pregnant, or (b) three menstrual cycles if she has regular
periods, or three calendar months if she no menses. For details and exceptions,
consult a book of Islamic jurisprudence
(Fiquh). During the
iddah the woman is not free to marry anyone else. If it is a reversible
divorce, her husband may choose to take her back at any time during the
iddah. If he does not take her back after the waiting period, the divorce
is final and the woman is free to marry someone else, or she may go back
to her husband with a new marriage contract, and he must Pay her a new
dower. (editor's note)