Analogy requires that it be one and a half menstruations, just as her legal punishment (hadd) is half that of a free woman, but menstruation cannot be divided into parts, so it is completed as two menstruations. For this reason, 'Umar, may Allah be pleased with him, said: 'If I were able to make the 'idda one and a half menstruations, I would have done so.' Once this is established, the expiration of her 'idda occurs upon performing ghusl from the second menstruation, according to one of the two narrations, and according to the other, it occurs upon the cessation of the blood from the second menstruation. According to the narration which states that the quru' are the periods of purity (at-athar), the expiration of her 'idda occurs upon seeing the blood from the second menstruation.

1342 - Issue; he said: (And if she is among those who have reached menopause, or among those who have not yet menstruated, her 'idda is three months)

Scholars have reached a consensus on this; because Allah the Almighty mentioned it in His Book, by His saying, the Exalted: {And those who no longer expect menstruation among your women - if you are in doubt, then their period is three months, and [likewise for] those who have not menstruated} (1). If the divorce occurs at the beginning of the lunar month, three months are calculated by the lunar phases (ahilla); because of the saying of Allah the Almighty: {They ask you, [O Muhammad], about the new moons. Say, 'They are measurements of time for the people and for Hajj'} (2). And He, the Exalted, said: {Indeed, the number of months with Allah is twelve [lunar] months in the register of Allah [from] the day He created the heavens and the earth; of these, four are sacred} (3). People do not disagree that the sacred months (4) are measured by the lunar phases. If the divorce occurs during the middle of a month (5), she waits for the remainder of it, then she waits for two months by the lunar phases, and then she waits from the third month for the completion of thirty days. This is the school of Malik, al-Shafi'i, and Abu Hanifah: she counts the remainder of the first, and she counts from the fourth an amount equal to what she missed from the first, whether it was complete or incomplete; because if it were from the beginning of the lunar month, the 'idda would be by the lunar phases, so if it were from part of the month, it is necessary to make up for what was missed of it.