Is a girl who was raped obligated to observe the waiting period ('iddah)?

Scholars have differed on the 'iddah (waiting period) of a woman if she commits zina (fornication/adultery), even if under duress, holding three opinions:

1. No 'Iddah for her: This is the madhhab of the Hanafis and Shafi'is, and Sheikh Ibn 'Uthaymeen chose this opinion if she is married. 2. Three menstrual cycles: This is the madhhab of the Malikis and Hanbalis. 3. One menstrual cycle: This is an opinion among the Malikis and a narration from Imam Ahmad, and Sheikh al-Islam Ibn Taymiyyah chose it.

Sheikh Ibn 'Uthaymeen preferred that if the woman who committed zina is married, she has no 'iddah and no istibra' (period of cleansing/waiting), based on the Prophet's (peace and blessings be upon him) saying: "The child belongs to the bed (i.e., the husband)." If she is not married, then she performs istibra' with one menstrual cycle.