Asma bint Abu Bakr reported,

She was pregnant with Abdullah bin Zubayr. She said, "I set out while I was full-term and arrived in Madinah, where I stayed at Quba and gave birth to him there. Then I came to the Prophet ﷺ and placed the baby in his lap. He called for a date, chewed it, and then placed some of it into the baby's mouth. So the first thing to enter his stomach was the saliva of the Messenger of Allah ﷺ. Then he rubbed the date on the baby's palate, prayed for him, and blessed him. He was the first child born into Islam."

Azami 8665

Sahih

عن أسماء

أنها حملت بعبد الله بن الزبير قالت: فخرجت، وأنا متم فأتيت المدينة، فنزلت بقباء، فولدته بقباء، ثم أتيت النبي ﷺ فوضعته في حجره، ثم دعا بتمرة فمضغها، ثم تفل في فيه. فكان أول شيء دخل جوفه ريق رسول الله ﷺ ثم حنكه بتمرة، ثم دعا له، وبرك عليه. وكان أول مولود ولد في الإسلام.

الأعظمي 8665صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Biography of the Prophet ﷺ
Chapter
Emigration of the Prophet ﷺ and his companions from Makkah to Madinah
Section
Asma emigrated to the Prophet ﷺ while she was pregnant
Numbering
Jami al-Kamil 8665 (2nd edition)
Azami 8665