This is something new. I received an email telling me about Baby Plus. According to the BabyPlus web site:

The BabyPlus Prenatal Education System is a set of sound lessons that are played to the prenatal child. This patented approach enhances learning ability. As your baby begins to recognize the difference between the rhythmic sounds of BabyPlus and the similar natural rhythms of the mother's heartbeat, learning begins.

You do everything possible to prepare your baby for birth - prenatal vitamins, exercise. etc. A new crib and all the other accoutrements wait in the nursery. Baby plus is another prenatal tool. It will help your baby to learn.

BabyPlus is a series of 16 scientifically designed sounds that resemble a mother's heartbeat. The rhythm of the sounds increases incrementally as the pregnancy progresses. The BabyPlus sonic pattern introduces your child to a sequential learning process, built upon the natural rhythms of their own environment.

Is it safe? The web site assures us it is:

Of course! There is no question that this is an entirely new field of education, but prenatal stimulation has been around for thousands of years. BabyPlus simply represents the evolution of enrichment in the womb to a technique that has incredible advantages for the child. We believe that, someday, the use of BabyPlus will be as much a part of being pregnant as is taking prenatal vitamins.