It is narrated from Abdullah bin Abdullah bin Abi Umayyah that a woman's husband died, and she observed an 'iddah of four months and ten days. Then, when she became lawful, she married, and she stayed with her husband for four and a half months, then gave birth to a fully formed child. Her husband came to Umar bin al-Khattab (may Allah be pleased with him) and mentioned the matter to him. Umar bin al-Khattab (may Allah be pleased with him) summoned women from the early days of the Jahiliyyah and asked them about this matter. One of those women said: I will tell you about this woman. Her husband, by whom she had become pregnant, died, and then her blood kept flowing, and her child dried up in her womb. When the husband whom she had married came to her and the water reached the child, the child moved in her womb and grew. Umar bin al-Khattab (may Allah be pleased with him) believed her and separated the two of them. Umar (may Allah be pleased with him) said: Nothing but good has reached me about you two. And he attributed the child to the first (husband).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15559