"The word idda is derived from the verb adda, meaning to count or enumerate. A woman whose marriage is annulled, or when she is divorced, a period of waiting, known as idda, is followed. The Koran says: "O Prophet! when you divorce women, divorce them for their prescribed time (idda), and calculate the number of the days prescribed, and be careful of (your duty to) God, your Lord. Do not drive them out of their houses, nor should they themselves go forth, unless they commit an open indecency; and these are the limits of God, and whoever goes beyond the limits of God, he indeed does injustice to his own soul. You do not know that God may after that bring about reunion" (65:1).
The prescribed time of waiting (idda) is about three months. The Koran says: "And the divorced woman should keep themselves in waiting for three courses (quru); and it is not lawful for them that they should conceal what God has created in their wombs, if they believe in God and the last day; and their husbands have a better right to take them back in the meanwhile if they wish for reconciliation" (2:228).
The word quru is the plural of qur or qar, meaning a time, menstruation, period or state of purity preceding and following a menstrual discharge, i.e., a period between two menstruation and that of purity taken together, i.e., the whole month. In normal cases, it is about four weeks, but there are variations in the case of different women. In the case of women who do not menstruate as well as those whose courses have stopped, the idda is three months (65:4). The general opinion, however, is that the woman should wait till the end of her third menstruation after divorce, and this period is taken to be known as idda. In the case of pregnant women, the waiting period (idda) is till delivery (65:4).
The idda among other purposes serves the purpose of affording the parties a chance of reconciliation. Though they are divorced, yet they still live in the same house, the husband being plainly told not to expel the wife from the house in which she has been living unless she is guilty of misconduct, and a similar advice is given to the wife not to leave the house (65:1). This injunction clearly aims at restoring amicable relations between the parties and minimizing chances of the accentuation of differences. If there is any love in the union, its pang would assert themselves during the period of waiting (idda) and bring about a reconciliation.
The prescribed time is ordinarily three months (2:228). But in the case of woman with child, and certain other cases, the prescribed time is laid down also in the Koran: "And (as for) those of your women who have despaired of menstruation, if you have a doubt, their prescribed time shall be three months, and of those too who have not had their courses; and (as for) the pregnant women, their prescribed time is that they lay down their burden; and whoever is careful of (his duty to) God, He will make easy for him his affair" (65:4).
In sum, Islam does not permit polyandry, a man may not validly marry a woman who is observing idda, a period of waiting imposed upon a wife after the termination of her marriage. Its prime purpose is to determine whether or not she is pregnant as a result of the marriage, and therefore she is not allowed to remarry during this time. Following divorce the idda lasts until the completion of three menstrual cycles or, where the wife proves to be pregnant, until the birth of the child. In case of widowhood the idda also lasts for a prescribed period of four months and ten days, or until the birth of the child in cases of pregnancy.
If a woman is not pregnant, her idda period is 3 months (2:228).
For virgin widow, there is no idda (33:49).
Four months and ten days for those women whose husbands died (2:234).
Where a man divorces a woman once or twice, but not three times, and dies before the idda of divorce is completed, the widow shall observe idda for 4 months and 10 days from the date of death, and she has the right to inherit from him. A woman whose husband is away (mughib), shall observe idda from the day when she receives word of his death. When a husband, who is away, divorces his wife, if the date of divorce is known, the wife shall observe idda from the date of divorce; and if the date of the divorce is not known, then from the date when she receives news of the divorce. When the husband is away from his home, and has divorced his wife before the marriage was consummated, the marriage terminates immediately, and there is neither idda nor ihdad (seclusion). It is also not proper (la yanbaghi) for a man to ask for the hand of a woman during her idda.
Islam has also permitted to undertake profession to the widow or the divorced woman during her idda, because if her work is necessary to her family, she is encouraged to carry on with her profession. Jabir bin Abdullah narrated: My maternal aunt was divorced, and she intended to pick her dates. A man scolded her for having come out during the period of idda. She came to the Prophet and he said, "Certainly you can pick dates from your palm trees, for perhaps you may give charity, or do an act of kindness" (vide Sahih Muslim-Sharh al-Nawawi, Cairo, 1972, 3:190).