Jami` at-Tirmidhi 1476
جامع الترمذي#1476SahihNarrated Abu Sa'eed:That the Prophet (ﷺ) said: "Slaughtering the fetus is (achieved by) the slaughtering of its mother
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 18:15