Abu Zubair says that I asked Sayyiduna Jabir (may Allah be pleased with him) about the ruling regarding a person who divorces his wife during her menstrual period. He replied that Sayyiduna Abdullah bin Umar had also once divorced his wife during her menstrual period. Sayyiduna Umar mentioned this to the Prophet (peace and blessings be upon him), so the Prophet (peace and blessings be upon him) said that he should take her back because she is his wife.