New research suggests fetuses respond to the rhythm of a nursery rhyme by 34 weeks' gestation and can remember that rhyme until birth.
In the study published recently in Infant Behavior and Development, researchers looked at pregnant women who recited a rhyme three times a day over the course of six weeks starting at the beginning of their third trimester, the University of Florida reported.
"The mother's voice is the predominant source of sensory stimulation in the developing fetus," Nursing researcher Charlene Krueger said. "This research highlights just how sophisticated the third trimester fetus really is and suggests that a mother's voice is involved in the development of early learning and memory capabilities. This could potentially affect how we approach the care and stimulation of the preterm infant."
To make their findings the researchers recruited 32 pregnant women who were in the 28th week of their first pregnancy and were between the ages of 18 and 39. The participants were split into either a control group or a control group.
Between 28 and 34 weeks of pregnancy the mothers were asked to recite a passage or nursery rhyme out loud twice a day and come in for testing at 28, 32, 33 and 34 weeks' gestation. The mothers were then asked to stop speaking the passage at 34 weeks to see if the fetus could remember it. The fetuses were tested again at 36 and 34 weeks' gestation.
To test the fetuses the researchers used a fetal heart monitor to measure changes in heart rate. A deceleration in heart rate indicates familiarity with a stimulus. The fetuses reponded to the rhymes as early as 34 weeks.The fetuses also responded to a stranger reciting the rhyme, suggesting they were not just responding to their mothers' voice.
"This study helped us understand more about how early a fetus could learn a passage of speech and whether the passage could be remembered weeks later even without daily exposure to it," Krueger said. "This could have implications to those preterm infants who are born before 37 weeks of age and the impact an intervention such as their mother's voice may have on influencing better outcomes in this high-risk population."
