In his 2011 book, The Religious Elite of the Early Islamic Hijaz, Asad Q. Ahmed demonstrated the importance of maternal kinship ties to the functioning of elite society in early Islamic Arabia. As Ahmed only focused his attention on the descendants of five Companions of the Prophet Muḥammad, many opportunities remain to investigate further how maternal kinship ties operated in this context. This paper will analyze Muḥammad Ibn Sa‘d’s (d. 230/845) Kitāb al-Ṭabaqāt al-Kubrā to trace the prevalence and importance of kinship ties between uterine brothers (half-brothers from the same mother) in early Islamic Arabia. First, this paper will mine Ibn Sa‘d’s data to reveal the prevalence of divorce/widowhood and remarriage for women, the practice of exogamy vs. endogamy in these remarriages, and the overall prevalence of uterine brotherhood. Second, it will conduct a close reading of the biographies of five mothers and their children from different fathers, to determine how Ibn Sa‘d presents the relationships of motherhood, childhood, and uterine brotherhood. These case studies are Sumayya bint Khayyāṭ, Jamīla bint Thābit, Umm Sulaym bint Milḥān, Khawla bint al-Manẓūr, and Asmā’ bint Salāma, and their respective children. Finally, traditional patrilineal representations of descent fail to illustrate maternal and sororal kinship ties. This paper will use the digital network analysis software Gephi to visually represent both the paternal/fraternal and the maternal/sororal kinship ties of the five case studies mentioned above, to illustrate the importance of female-based kinship ties in early Islamic history.