Yahya related to me from Malik from Ibn Shihab that Said ibn al-Musayyab said, "The idda of the woman who bleeds constantly is ayear."Malik said, "What is done among us about a divorcedwoman whose periods stop when her husband divorces her is that shewaits nine months. If she has not had a period in them, she has anidda of three months. If she has a period before the end of the threemonths, she accepts the period. If another nine months pass withouther having a period, she does an idda of three months. If she has asecond period before the end of those three months, she accepts theperiod. If nine months then pass without a period, she does an idda ofthree months. If she has a third period, the idda of the period iscomplete. If she does not have a period, she waits three months, andthen she is free to marry. Her husband can return to her before shebecomes free to marry unless he made her divorce irrevocable."Malik said, "The sunna with us is that when a man divorces hiswife and has the option to return to her, and she does part of heridda and then he returns to her and then parts from her before he hashad intercourse with her, she does not add to what has passed of heridda. Her husband has wronged himself and erred if he returned to herand had no need of her."Malik said, "What is done among usis that if a woman becomes a muslim while her husband is a kafir andthen he becomes muslim, he is entitled to her as long as she is in heridda. If her idda is finished, he has no access to her. If heremarries her after the end of her idda, however, that is not countedas divorce. Islam removed her from him without divorce."
USC-MSA web (English) reference: Book 29, Hadith 71
Arabic reference: Book 29, Hadith 1232