Abu Sa’id Al Khudri traced to Prophet ﷺ the following statement regarding the captives taken at Atwas. There must be no intercourse with pregnant woman till she gives birth to her child or with the one who is not pregnant till she has had one menstrual period. (Using translation from Abū Dāʾūd 2157)  

أَنَّهُ قَالَ فِي سَبَايَا أَوْطَاسٍ «لَا تُوطَأُ حَامِلٌ حَتَّى تَضَعَ حَمْلَهَا وَلَا غَيْرُ ذَاتِ حَمْلٍ حَتَّى تَحِيضَ حَيْضَةً»