Pregnant women have long been encouraged to chat and sing to their unborn children, and now new research shows that fetuses respond to sounds as early 16 weeks gestation, as opposed to the 23 weeks that doctors have long believed. The findings, published this week in the British journal Ultrasound, could lead to more advanced fetal diagnostic tools in the future.
Researchers at the Institut Marquès in Barcelona created a device that emitted music and could be inserted into the mother’s vagina. Once the music played inside the mother — Bach’s Partita in A Minor for Flute Alone – BWV 1013, to be exact — ultrasounds showed the fetuses opened their mouths and stuck their tongues out as far as possible. When music was played outside the mothers’ bodies, the fetuses did not respond. The findings suggest the auditory–motor system develops as early as 16 weeks gestation, but the fetuses simply cannot yet hear the sounds outside of mothers’ body.
“The soft tissues of the abdomen and the inside of the mother’s body absorb the soundwaves,” says Dr. Marisa López-Teijón, head of assisted reproduction at Institut Marquès and lead author of the study. She and her team believe sounds activate brain circuits that stimulate language and communication, and the device, which was created specifically for the study, may help diagnose fetal deafness in the future.
“We can say learning begins in the womb,” says López-Teijón.