That the Prophet ﷺ said: "Slaughtering the fetus is (achieved by) the slaughtering of its mother."  

عَنِ النَّبِيِّ ﷺ قَالَ ذَكَاةُ الْجَنِينِ ذَكَاةُ أُمِّهِ قَالَ وَفِي الْبَابِ عَنْ جَابِرٍ وَأَبِي أُمَامَةَ وَأَبِي الدَّرْدَاءِ وَأَبِي هُرَيْرَةَ