It is never too late to get stuck in and feed on the word of The Living God regardless of the stage of your pregnancy. Firstly there is no substitute for the Bible and of course its good to get in there and communicate with papa God, to meditate on His word and to just be surrounded by His word.
The Bible offered me (and still does) a secret place of rest where i could lay it all down at the feet of The Lord during both my pregnancies. I can testify that God directed me to various scriptures which i used to confess it out loud over myself and both babies. The Lord also directed me in other areas such as choosing the right names etc.. God is amazing the way He cared and cares for me and the little things.
There are many devotionals available these days are specifically catered for pregnant ladies (really we are too spoilt these days). I did not use a devotional but had a fantastic book recommended to me by a sister from church. She recommended a supernatural childbirth by Ms Jackie Mize which I found both enjoyable and practical so i would happily recommend it and the rest of their pregnancy books to any mum to be.