Newborn; just born or very recently born. Often used for babies or young animals; can be used figuratively for something brand-new.
生まれたての赤ちゃんはよく眠る。
Newborn babies sleep a lot.
庭で生まれたての子猫を見つけた。
I found a newborn kitten in the yard.
そのベンチャーは生まれたてで、まだ社員も少ない。
That startup is brand-new and still has only a few employees.