It is narrated from Ata' that Aishah (may Allah be pleased with her) took her sister for Hajj during her 'iddah.
It is narrated from al-Qasim that it was a time of fear of turmoil, that is, at the time when Aishah (may Allah be pleased with her) took her sister for Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15509