A woman with postnatal bleeding or menstruation does not make up the prayers of the days of menstruation and postnatal bleeding

Mussah al-Azdiyyah narrates: I performed Hajj and went to Sayyidah Umm Salamah (may Allah be pleased with her) and said: "O Mother of the Believers, Sayyiduna Samurah bin Jundub (may Allah be pleased with him) orders women to make up the prayers missed during the days of menstruation." She said: "They should not make them up. Any woman among the wives of the Prophet (peace and blessings be upon him) who was in postnatal bleeding would remain (from prayer) for forty nights, and the Prophet (peace and blessings be upon him) did not order her to make up the prayers of the postnatal period."
This hadith has a sahih (authentic) chain, and there is also a supporting report for it.

Sayyidah Umm Salamah (may Allah be pleased with her) narrates: In the blessed time of the Messenger of Allah (peace and blessings be upon him), women in postnatal bleeding would remain (from prayer) for forty days or forty nights, and we (after childbirth) would apply wars (a yellow plant dye) to our faces because of dark blemishes.

Ibn Abi Mulaykah narrates: My maternal aunt, Fatimah bint Abi Hubaysh, came to Sayyidah Aishah (may Allah be pleased with her) and said: "I fear that I will fall into the Fire (of Hell), for I leave the prayer for a year or two at a time." She said: "Wait until the Prophet (peace and blessings be upon him) comes." When he (peace and blessings be upon him) came, Sayyidah Aishah described the situation, and the Prophet (peace and blessings be upon him) said to her: "Tell her to leave the prayer every month during the days of her menstruation, then take one ritual bath every day, then perform ablution at the time of every prayer, clean herself and bind a cloth, for this is an illness, or a strike from Satan, or due to a severed vein."
This hadith is sahih (authentic), but the two Shaykhs did not record it with this wording, and Uthman bin Sa'd of Basrah is trustworthy (thiqah).