وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ سُئِلَ عَنِ الْمَرْأَةِ، يُتَوَفَّى عَنْهَا زَوْجُهَا وَهِيَ حَامِلٌ فَقَالَ عَبْدُ اللَّهِ بْنُ عُمَرَ إِذَا وَضَعَتْ حَمْلَهَا فَقَدْ حَلَّتْ ‏.‏ فَأَخْبَرَهُ رَجُلٌ مِنَ الأَنْصَارِ كَانَ عِنْدَهُ أَنَّ عُمَرَ بْنَ الْخَطَّابِ قَالَ لَوْ وَضَعَتْ وَزَوْجُهَا عَلَى سَرِيرِهِ لَمْ يُدْفَنْ بَعْدُ لَحَلَّتْ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umarwas asked about a woman whose husband died while she was pregnant, andhe said, "When she gives birth, she is free to marry." A man of theAnsar who was with him told him that Umar ibn al-Khattab had said,"Had she given birth while her husband was still on his bed, unburied,she would be free to marry." Translation Not Available

Book Ref: Muwatta Imam Malik Book 29 Hadith 1247
Web Ref:  Muwatta Imam Malik Book 29 Hadith 84