It's scriptural.

Luke 1:41-45

[41] And it came to pass, that when Elizabeth heard the salutation of Mary, the infant leaped in her womb. And Elizabeth was filled with the Holy Ghost: [42] And she cried out with a loud voice, and said: Blessed art thou among women, and blessed is the fruit of thy womb. [43] And whence is this to me, that the mother of my Lord should come to me? [44] For behold as soon as the voice of thy salutation sounded in my ears, the infant in my womb leaped for joy. [45] And blessed art thou that hast believed, because those things shall be accomplished that were spoken to thee by the Lord.