Do not corrupt for us the practice of our Prophet Muhammad ﷺ. The waiting period of an umm walad is four months and ten days.
حدثنا علي بن محمد حدثنا وكيع عن سعيد بن أبي عروبة عن مطر الوراق عن رجاء بن حيوة عن قبيصة بن ذؤيب
لا تفسدوا علينا سنة نبينا محمد ﷺ عدة أم الولد أربعة أشهر وعشرا
Its chain of transmission is daif. Abu Dawud narrated it in the Book of Divorce, chapter on the waiting period of a slave-woman who has borne her master's child, hadith no. 2308, from [ ] Abu Dawud, the hadith of Saeed with this wording. Ibn Hibban graded it sahih in (Mawarid), hadith no. 1333, as did Hakim, who said it meets the standard of the two Shaykhs (Bukhari and Muslim), 2/209, and Dhahabi agreed with him.Ahmad said, "This is a denounced hadith." Daraqutni said, "It is disconnected, because Qabisa never heard from Amr," 4/31, and Bayhaqi followed him in this. So the chain has a hidden defect.