من لا يحضره الفقيه, volume 2, page 187

Hadith.2098 - It is narrated from Dawud ibn Sirhan, who said: "I was in Medina during the Month of Ramadan, and I said to Abu Abdullah (as): 'I wish to perform i'tikaf. What should I say, and what should I make obligatory upon myself?' Imam (as) said: 'Do not leave the mosque except for an unavoidable necessity, and do not sit under any shade until you return to your place in the mosque.'"

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.2099 - It is narrated by Al-Halabi, from Abu Abdullah (as), who said: "It is not appropriate for the one performing i'tikaf to leave the mosque except for an unavoidable necessity, and they should not sit until they return. They should only leave for attending a funeral or visiting a sick person, and even then, they should not sit until they return to the mosque. The i'tikaf of a woman is the same as this."

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.2100 - In a narration from Safwan ibn Yahya, from Abdur-Rahman ibn Al-Hajjaj, from Abu Abdullah (as), it is reported: "If the one performing i'tikaf falls ill, or if the woman performing i'tikaf experiences menstruation, they may return to their home. Once they recover, they should resume their i'tikaf and complete it while fasting."

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.