وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ أَسْمَاءَ بِنْتَ عُمَيْسٍ، وَلَدَتْ، مُحَمَّدَ بْنَ أَبِي بَكْرٍ بِذِي الْحُلَيْفَةِ فَأَمَرَهَا أَبُو بَكْرٍ أَنْ تَغْتَسِلَ، ثُمَّ تُهِلَّ ‏.‏

Yahya related to me from Malik from Yahya ibn Said from Said ibnal-Musayyab that Asma bint Umays gave birth to Muhammad ibn Abi Bakrat Dhu'l-Hulayfa and Abu Bakr told her to do ghusl and then enterihram. Translation Not Available

Book reference: Muwatta Imam Malik Book 20 Hadith 709
Web reference: Muwatta Imam Malik Book 20 Hadith 2