Praise be to Allah.
It is haraam for the person who is junub (in a state of impurity following sexual activity) to pray, perform tawaaf, stay in the mosque, recite Quran or touch the Mushaf. Everything else is permissible.
There is nothing wrong with a woman who is junub cooking, looking after her house, taking care of her children or fulfilling any other needs. This is indicated by several pieces of evidence including the following:
(a)It was narrated from Abu Hurayrah that the Prophet (peace and blessings of Allah be upon him) met him on one of the roads of Madeenah when he was junub. He said: I turned back and went and did ghusl, then I came. He said: “Where were you, O Abu Hurayrah?” I said: “I was junub and I did not like to sit with you when I was not in a state of purity.” He said, “Subhaan Allah, the Muslim does not become impure.”
Narrated by al-Bukhaari, 279; Muslim, 371.
Al-Haafiz ibn Hajar said: This indicates that it is permissible to delay doing ghusl from the time when it first becomes obligatory, and that it is permissible for the one who is junub to go about his business.
Fath al-Baari, 1/391.
It is better for the one who is junub to hasten to do ghusl, lest he forgets that he is junub. And it is recommended for him to do wudoo’ before he touches food and drink and before going to sleep. That is better than doing these things when he is junub. But this wudoo’ is not obligatory, rather it serves to reduce the impurity, and it is mustahabb. There are a number of ahaadeeth concerning that, including the following:
(i)It was narrated that ‘Aa’ishah said: When the Messenger of Allah (peace and blessings of Allah be upon him) was junub and wanted to eat or sleep, he would do wudoo’ as for prayer. (Narrated by Muslim, 305).
(ii)It was narrated from Ibn ‘Umar that ‘Umar ibn al-Khattaab asked the Messenger of Allah (peace and blessings of Allah be upon him), “Can one of us go to sleep when he is junub?” He said: “Yes, if he does wudoo’ then he can go to sleep when he is junub.” (narrated by al-Bukhaari, 283; Muslim, 306)
Al-Nawawi said: This indicates that it is mustahabb to do wudoo’ and to wash one's private parts before doing all these things, especially if the man wants to have intercourse with a wife with whom he has not yet had intercourse. It is definitely mustahabb to wash one's private part. Our companions have stated that it is makrooh to sleep, eat, drink or have intercourse before doing wudoo’, and these ahaadeeth indicate that. There is no dispute among us that this wudoo’ is not obligatory. This is also the view of Maalik and the majority.
Sharh Muslim, 3/217
Shaykh al-Islam Ibn Taymiyah said:
It is mustahabb for the one who is junub to do wudoo’ if he wants to eat, drink, sleep or have intercourse again, but it is makrooh for him to sleep if he has not done wudoo’. It was proven in al-Saheeh that the Prophet (peace and blessings of Allah be upon him) was asked, “Can one of us go to sleep when he is junub?” He said: “Yes, if he does wudoo’ as for prayer…”
Majmoo’ al-Fataawa, 21/343
See also question no. 6533.
And Allah knows best.