A.T. Robertson Commentary Luke 1:41

"And it came to pass, when Elisabeth heard the salutation of Mary, the babe leaped in her womb; and Elisabeth was filled with the Holy Spirit;" — Luke 1:41 (ASV)

Leaped (εσκιρτησεν). A common enough incident with unborn children (Genesis 25:22), but Elisabeth was filled with the Holy Spirit to understand what had happened to Mary.