وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ كَانَ يَقُولُ يُنْهَى أَنْ تُنْكَحَ الْمَرْأَةُ عَلَى عَمَّتِهَا أَوْ عَلَى خَالَتِهَا وَأَنْ يَطَأَ الرَّجُلُ وَلِيدَةً وَفِي بَطْنِهَا جَنِينٌ لِغَيْرِهِ ‏.‏

Yahya related to me from Malik from Yahya ibn Said that Said ibnal-Musayyab said, "It is forbidden to be married to a woman and herpaternal or maternal aunt at the same time, and for a man to haveintercourse with a female slave who is carrying another man's child." Translation Not Available

Book Ref: Muwatta Imam Malik Book 28 Hadith 1115
Web Ref:  Muwatta Imam Malik Book 28 Hadith 21