Mother’s voice is no stranger, study of fetal responses finds

A developing fetus begins to hear at about 30 weeks, and now researchers have learned that as the delivery date approaches, a fetus begins to distinguish its mother’s voice from that of a stranger.

Sixty Chinese women were divided into two groups, and fetal heart rates were measured before, during and after a pre-recorded two-minute poem was played through a speaker held above the mother’s abdomen.

The heart rate increased about five beats a minute in 21 of the 30 fetuses who heard recordings of their mothers’ voices. Heart rates slowed about four beats a minute in 21 of the 30 fetuses who heard a recording of a stranger’s voice.

“There’s some sort of representation that the fetus is matching with the sound,” says lead author Barbara S. Kisilevsky, a professor of nursing and obstetrics and gynecology at Queen’s University in Kingston, Canada.

This study was published in the May issue of Psychological Science.

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Dianne Partie Lange