They should not do so. The Prophet's wives would refrain (from prayer) for forty days during postpartum bleeding, and the Prophet (may Allah's peace and blessings be upon him) would not command them to complete the prayers abandoned during that period

Umm Salamah (may Allah be pleased with her) corrected a Fatwa given by the noble Companion Samurah ibn Jundub (may Allah be pleased with him) where he commanded women to make up for the prayers abandoned during their menses. She said: "They should not do so," citing as evidence for her opinion that "the Prophet's wives would refrain (from prayer) for forty days during postpartum bleeding, and the Prophet (may Allah's peace and blessings be upon him) would not command them to complete the prayers abandoned during that period." There is something confusing here, as Mussah asked Umm Salamah about the ruling on prayer in terms of menses, informing that Samurah commanded women to make up for them, but Umm Salamah gave her reply involving the prayer during the postpartum period. To clear this confusion, we say: First: Menstrual period in the question was meant to refer to the postpartum period, as indicated by the reply. Second: Umm Salamah gave her reply concerning prayer during the postpartum period, which is shorter in duration than the menstrual period, for the menses occur 12 times every year, unlike the postpartum period. So, she clarified that the Almighty Lawgiver pardoned women in terms of the prayer abandoned during the postpartum period which rarely recurs; so what about the menses which come frequently; and Allah knows best.