Muwatta Malik 1041
موطأ مالك#1041SahihYahya related to me from Malik from Nafi that Abdullah ibn Umar did not sacrifice for the child in the womb. Malik said, "The sacrifice is sunna, and it is not obligatory. I prefer that anyone who has the price of the animal should not abandon it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 23:1