Researchers at the University of Helsinki in Finland examined 33 mothers during their third trimester of pregnancy. Out of the 33 participants, 17 listened to a CD that loudly played two, four-minute sequences of the made-up words "tatata" or "tatota," pronounced differently with varying pitches from week 29 to birth.
The words were repeated 50 to 71 times. Following birth, all 33 babies were tested for normal hearing and then were scanned with an EEG (electroencephalograph) to see if the newborns reacted differently to the same made-up words they were exposed to in the womb.
Researchers found the babies who listened to the CD recognized the words and were able to distinguish between the pitch changes due to increased brain activity. The babies who did not hear the CD in utero did not have increased brain activity, thus were not able to recognize the words or distinguish pitch changes. LINK