It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When the newborn cries out, he will be made an heir."
In one narration the wording is: "That is the jab of Satan; every one of the children of Adam receives it, except Maryam and her son, because when she was born her mother said: 'And I seek refuge for her with You, and for her offspring, from Satan the accursed' [Surah Al Imran: 36], so Satan jabbed at her through a veil."
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Satan jabs every child of Adam in his side when his mother gives birth to him, except Isa son of Maryam; he (Satan) went to jab him, but jabbed the veil." Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: I have seen this scream that the child lets out when his mother gives birth to him; it is from that (jab of Satan).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12485
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that it is established from the Sunnah that a newborn neither inherits nor is inherited from until it cries out. I found it like this; and Yahya bin Sa'id narrated from Sa'id bin al-Musayyib (may Allah have mercy on him) that the Messenger of Allah (peace and blessings be upon him) said: "The child does not inherit until it cries out," and al-istihlal means: "shouting, sneezing or crying," and his blood money will not be paid in full. Sa'id (may Allah have mercy on him) said: No funeral prayer is to be offered over him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12486
Sayyidah Aishah (may Allah be pleased with her), the wife of the Prophet (peace and blessings be upon him), said that Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) said regarding the wasqs (of dates) which he had given to Sayyidah Aishah (may Allah be pleased with her): "If you had cut them and taken possession of them, they would be yours; otherwise, from today they are the property of the heirs, and they are your two brothers and two sisters, so divide it according to the Book of Allah." Sayyidah Aishah (may Allah be pleased with her) said: "By Allah, O my father! If it were such and such, I would have left it. There is only one sister, Asma (may Allah be pleased with her); who is the other?" Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) said: "The one in the womb of the daughter of Kharijah; I think she is a girl."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12487
The wife of Zayd bin Thabit (may Allah be pleased with him) said: One day Zayd bin Thabit came to me and said: If you have a need, shall we speak to him about your inheritance from your father? For the Commander of the Believers, Umar bin al-Khattab (may Allah be pleased with him), has made the unborn child an heir. And Umm Sa'd was in the womb at the time her father was killed. Umm Sa'd said: I will not take anything from my sisters.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12488