When Elizabeth heard Mary’s greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit. In a loud voice she exclaimed: “Blessed are you among women, and blessed is the child you will bear! But why am I so favored, that the mother of my Lord should come to me? As soon as the sound of your greeting reached my ears, the baby in my womb leaped for joy. Blessed is she who has believed that the Lord would fulfill his promises to her! (Luke 1:41-45)
We feel nudges. Wise men and women act on them as did the poor shepherds in fields where they lay keeping their sheep on a cold winter’s night that was so deep. They looked up and saw a star shining in the east beyond them far. And to the earth it gave great light And so it continued both day and night. And by the light of that great star, three wise men came from country far. On The First Noel. https://www.youtube.com/watch?v=GoeecAbmvHw Why did the poor shepherds follow the Star of Bethlehem? God wanted them to be there. They felt His nudge, and wisely they went. (The story of the wise men (Magi) is in Matthew 2:1-12)
Through Gabriel, God nudged Mary to visit Elizabeth. In the presence of Mary, the Holy Spirit jumps from Mary’s womb to Elizabeth, telling her Mary is pregnant with God’s Son. Unborn baby John leaps, and the Holy Spirit discloses that John is joyful. The Holy Spirit conveys that Elizabeth is blessed with the presence of Mary and Jesus because she was faithful, believing the Lord would fulfill His promises to her.
Can an unborn baby leap for joy? Of course, when filled with the Holy Spirit. Then, John and Jesus could also bond as Elizabeth and Mary did. John deeply loved Jesus on the day he baptized Him, yet this was their only visit prior to that baptism. So, in addition to Mary visiting Elizabeth to prepare for her miracle and to bless Elizabeth, Mary went for John and Jesus to bond.