The Earliest Fetal Memory?

July 15, 2009— -- Like any prospective mom, as 21-year-old Angela Morton goes through her first pregnancy the family stories of her own baby years begin to emerge -- including her mother's trick of calming her with Aerosmith's 1988 song "Angel" anytime she was a fussing as an infant.

"That was the song for me I guess," said Morton. "But I've never even heard it since I was a baby."

Morton's mother may have discovered a secret infant-soothing property in Steven Tyler's rock ballads. Or, more likely, she was was playing on an aspect of fetal memory outlined by researchers in Tuesday's issue of the journal Child Development.

In a study of 100 of pregnant women in the Netherlands, researchers say they found evidence that fetuses have short-term memory of sounds by the 30th week of pregnancy, and develop a long-term memory of sound after that.

The researchers documented the memory by watching fetal movements with ultrasound while they played "vibroacoustic" sound to the growing baby. Five of the fetuses in the study did not move in reaction to the sound and were eliminated from the study.

But among the fetuses who did move, researchers repeated the sound until the fetus "habituated" to it and no longer reacted. Doctors let some time pass and then tested the memory of the fetus by playing the sound in intervals to see if the fetus "remembered" or recognized the sound and did not react.

The study found that by 30 weeks of age, a fetus could "remember" a sound for 10 minutes. By the 34th week a fetus may be able to "remember" the sound for four weeks.

Morton thought that same sort of memory could have been why she was calmed by Steven Tyler as an infant.

"She [Morton's mother] used to go play it when she pregnant and sing along… then when I was fussy as a baby she used to play it and I calmed down," she said.

Right now Morton mostly plays Christian rock and The Beatles for her baby boy Christian, who is due in November. She says she's thinking about expanding the music collection for her baby in case there is more to this research.