This is the story of how we discovered what babies hear inside the uterus and how they react when they hear sound. I’ll explain it step by step.

(1) WE HAD TO PLAY MUSIC TO THE FETUSES

After achieving better results in in-vitro fertilization by applying music vibrations in the incubators for embryos, we felt that the next step was to play music to the fetuses.

The first thing we did was to place speakers on the abdomen of pregnant women to a very high intensity (the equivalent to an airplane taking off), and when we performed the ultrasound, we saw that the fetus showed no reaction. In fact, gynecologists had never observed in an ultrasound a change on the fetus as a reaction to external noises or the voice of the mother. Therefore, we thought that maybe the fetuses didn’t hear it: the same way they can see, but they don’t see because there is no light; they probably can hear, but they don’t because the sound barely reaches them. This is how we decided that we had to bring closer to them the source of sound… we had to bring the background music into the uterus. And I had the idea of inserting a speaker in the vagina of pregnant women.

Indeed, during many months people was laughing at me, but when I explained it to my friend Luis Pallarés, computer engineer (and as we realized down the line, an expert in electronics), I realized that he wasn’t laughing at the idea, and instead he started working on it. In only a few weeks he designed a device with speakers and battery that could be connected to and external source of sound. That was our first prototype!

The first ultrasound was of our colleague Ana, a biologist of our team, who was 6 months pregnant. At the start of the ultrasound, the fetus was asleep, then we turned on the device and played Spanish guitar music and the fetus woke up… he started moving his mouth and tongue… It looked like he was singing or talking! We were in shock while Paco de Lucía kept on playing his guitar!