1. If any pillar of ‘Umrah is omitted, the ‘Umrah will not be valid. However, once that pillar is performed, the ‘Umrah will become valid.
2. If any obligatory act of ‘Umrah is omitted, the ‘Umrah will become valid if that act is performed again. If that is not possible, there is an opportunity to rectify it by offering a dam.
3. If a person has sexual intercourse while in the state of ‘Umrah, and this occurs before performing tawaf of the House of Allah, then, by unanimous agreement, his ‘Umrah will become invalid. If it occurs after tawaf but before sa‘i between Safa and Marwah, then according to the majority of scholars, his ‘Umrah will still become invalid. However, in all circumstances, he must continue and complete the rites of this invalidated ‘Umrah. He must then make it up and slaughter a hady. If intercourse occurs after performing tawaf of the House of Allah and sa‘i between Safa and Marwah but before trimming or shaving the hair, then although his ‘Umrah will be valid, he must slaughter a goat as fidyah. A similar report has been narrated from Ibn ‘Abbas (may Allah be pleased with him).[1]
[1]. Al-Bayhaqi: 5/127; Adwa’ al-Bayan 5/389; Al-Istidhkar 12/290.