Babies in the womb capable of recognising nursery rhymes

The ability of babies to learn even when they are in the womb should not be underestimated, according to researchers, who found unborn babies can recognise nursery rhymes by the time the mother is 34 weeks pregnant.

Many pregnant mums try and give their children auditory stimulation by playing them Mozart or Beethoven, but the researchers from Florida University found auditory stimulation works best when it is done by the mother.

The study published in the journal Infant Behavior and Development shows babies in utero begin to respond to the rhythm of a nursery rhyme — showing evidence of learning — by 34 weeks of pregnancy and are capable of remembering a set rhyme until just prior to birth.

Nursing researcher Charlene Krueger and her team studied pregnant women who recited a rhyme to their babies three times a day for six weeks, beginning at 28 weeks’ gestational age, which is the start of the third trimester of pregnancy.

They found when a female stranger recited the same nursery rhyme at 34 weeks, the baby’s heart rate changed showing it had recognised the rhyme.

“The mother’s voice is the predominant source of sensory stimulation in the developing fetus,” said Charlene Krueger, associate professor in the University of Florida’s College of Nursing. “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.”

From 28 to 34 weeks of pregnancy, all mothers in the study recited a passage or nursery rhyme out loud twice a day and then came in for testing at 28, 32, 33 and 34 weeks’ gestation. To determine whether the unborn baby could remember the pattern of speech at 34 weeks of age, all mothers were asked to stop speaking the passage. Then the unborn babies were tested again at 36 and 38 weeks’ gestational age.

The researchers used a fetal heart monitor to record heart rate and determine any changes. Researchers interpret a small heart rate deceleration in the unborn baby as an indicator of learning or familiarity with a stimulus.

At testing, the unborn babies in the experimental group were played a recording of the same rhyme their mother had been reciting at home but spoken by a female stranger. Those in the control group heard a different rhyme also spoken by a stranger. This was to help determine if the unborn baby was responding simply to its mother’s voice or to a familiar pattern of speech, which is a more difficult task.

The researchers found that the unborn baby’s heart rate began to respond to the familiar rhyme recited by a stranger’s voice by 34 weeks of gestational age — once the mother had spoken the rhyme out loud at home for six weeks.

They continued to respond with a small cardiac deceleration for as long as four weeks after the mother had stopped saying the rhyme until about 38 weeks. At 38 weeks, there was a statistically significant difference between the two groups in responding to the strangers’ recited rhymes — the experimental group who heard the original rhyme responded with a deeper and more sustained cardiac deceleration, whereas the control group who heard a new rhyme responded with a cardiac acceleration.

“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,” Professor Krueger added.

“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.”