Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 1:39-45

“But because there have been other holy women who yet have borne sons stained with sin, she adds, And blessed is the fruit of thy womb. Or another interpretation is, having said, Blessed art thou among women, she then, as if some one enquired the cause, answers, And blessed is the fruit of thy womb: as it is said, Blessed be he that cometh in the name of the Lord. The Lord God, and he hath shewed us light; (Ps. 118:26, 27.) for the Holy Scriptures often use and, instead of because.”