Scott Hahn has written a great piece on the connections between the Holy Spirit and the Blessed Virgin Mary. I didn't read all of it but it really helped me to understand the maternal aspects of the Spirit - though obviously the Holy Spirit is not feminine as Hahn makes clear, but in the same way that God the Father is not male, we can use analogies to understand God.
Anyway he writes about how the Spirit conceived in Mary brought forth the birth of Christ and how the Spirit's work in baptism gives birth to Christians etc. He quotes N.T. Wright which will only confirm the widespread allegations that Wright is a secret Jesuit (though I think the man is very anti-Catholic)
Anyway, here is the book: