Does not performing the correct ghusl after menstruation following zinā prevent the womb from being cleared, and can she marry now?

If a woman repents from fornication (zina), she is only required to repent, and her marriage is valid. Her previous inadequate ghusl does not affect the validity of her marriage. The 'istibra' (cleansing of the womb) for a fornicator has no relation to ghusl; rather, it is accomplished by the passing of three menstrual cycles or one menstrual cycle. Some scholars are of the opinion that she does not require an 'iddah (waiting period) or 'istibra'. Al-Kasani and Al-Shirazi mentioned that a fornicator has no 'iddah, while Al-Dardir and Al-Suqi mentioned the obligation of 'istibra' with three menstrual cycles. Ibn Qudamah said that her 'iddah is like that of a divorced woman, and the expiry of her 'iddah is a condition for the permissibility of their marriage.