Some Aspects of the Fetal Sound Environment

Abrams, R. M. (1995). In I. Deliège & J. A. Sloboda (Eds.), Perception and cognition of music(pp. 83–101).Philadelphia, PA: Psychology Press.

Abrams reviews the results of research in humans and sheep regarding the ability of the fetus to hear sounds. This article, while not a detailed research report, is included because it provides an accessible summary of a number of important technical medical studies:

• By twenty-four weeks, the cochlea and peripheral sensory end organs of the fetus have reached their normal development, and by twenty-six weeks most fetuses will respond with increased heart rate to sound stimulation, indicating that they are able to perceive sounds. The inner ear of the fetus is fully functioning during the last trimester of pregnancy.
• The fetal sound environment is "heavily dominated by mother's voice and other internal noises and permeated by rich and diversified rhythmic and tonal surrounding sounds." (Abrams, 1995, p. 83) The internal noises include the mother's breathing, cardiovascular and intestinal activity, physical movements, "fetal cardiovascular pulsations," and building vibrations of very low frequencies (below 50Hz).
• To be perceived by the fetus, outside sounds must be louder than the "noise floor" (sounds of the fetal environment). At frequencies below 60Hz (the approximate frequency of the lowest note on the piano), the noise floor is about eighty decibels (dB). From 60–250Hz, the noise level is less than 60dB. Above 60Hz, the noise floor is about 60dB.
• The fetus will probably not hear airborne sounds above 500–1000Hz unless the sounds are uncomfortably loud for the mother. However, lower frequency sounds are heard by the fetus at comfortable listening levels for the mother. Therefore, "the fetus is probably detecting only the fundamental frequencies of a musical passage. Very little high frequency information would be detected" (Abrams, 1995, p. 99).

Prelude to a Musical Life: Prenatal Music Experiences

Shetler, D. J. (1985). Music Educators Journal, 71,(7), 26–27.

Note: This was not a tightly controlled study. The author himself indicates that the study and its results are preliminary. However, in light of the fact that studies regarding the effect of prenatal music stimulation are few, I found the results interesting and worth including.

Research Design:
Descriptive Case Study
N = 16

Purpose:
The purpose of this study was to determine the effect of systematic prenatal musical stimulation by observing musical behaviors exhibited between birth and six years of age.

Procedure:
Sixteen babies and their parents participated in this study. Some of the babies (the article does not indicate how many) were serenaded before birth by "stimulative" or "sedative" types of music. For many, the home environment was rich with musical stimulation. After birth, the babies and their parents visited the investigator at least once every sixty days. The babies were observed, and their responses and activities were documented. The babies listened to recorded and live sounds, including short rhythmic and melodic fragments. Echo or imitative responses were documented. Sounds made by the baby during free-play activities when "sound toys" were introduced were also noted. Children three years and older sang or played the piano and other instruments, and their activities were observed and documented. Developmental growth was also discussed with the mother and, in some cases, other family members.

Results:
The infants who received systematic prenatal musical stimulation exhibit "remarkable attention behaviors, imitate accurately sounds made by adults (including nonfamily members), and appear to structure vocalization much earlier than infants who did not have prenatal musical stimulation" (Shetler, 1985, p. 27).
 

Prenatal and Postnatal Responses to Music and Sound Stimuli: A Clinical Report

Wilkin, P. E. (1993). In T. Blum (ed.), Prenatal perception, learning and bonding (pp. 307–29). Berlin: Leonardo Publishers.

An update of this study also appeared in the Bulletin of the Council for Research in Music Education in Winter 1995/96, 3, pp.105–108, under the title "Comparison of fetal and newborn responses to music and sound stimuli with and without daily exposure to a specific piece of music." The 1991 study utilized a control group of only six women. This update describes the comparison between the results of the 1993 study and a larger control group that was studied after the book article was published. The following summary combines information from both sources.

Research Design:
A pretest and a posttest were conducted.
Experimental Group: N = 32
Control Group: N = 34

Purpose:
The purpose of this study was to determine the effect of daily listening of music on fetuses and newborns.

Procedure:
The test-group fetuses were monitored for fetal movements and heart rate at thirty-two and thirty-eight weeks gestation. Following ten minutes of monitoring with no stimulus, headphones were secured to the mother's abdomen and covered with a pillow, and a tape was played. The mother was also asked to write down the number and type of movements the fetus made for each item on the tape. (The mothers were prevented from hearing the tape in order to limit their recordkeeping to a purely fetal response.) The four items on the test tape were each five minutes long:

• White noise
• Piano solo: Beethoven's Piano Sonata, op. 31 no. 2, in D minor ("The Tempest")
• Choral (a cappella): Palestrina's "Kyrie" from Missa Pape Marcelli
• Rock (instrumental): Emerson, Lake, and Palmer from An Anthology of Rock.
   

The test group was also were given a tape of either item two or three to play for their fetuses on a daily basis from thirty-two weeks gestation and for six weeks after birth. The contents of the test tape and the home tape were not revealed to the women until a home visit at four to six weeks. The control group of thirty-four pregnant women was given no specific listening tasks and was monitored at thirty-eight weeks only. At six weeks, the babies of both groups were again monitored while the tape was played. They were scored on the following:

• Number of movements
• Eyes open
• Still and listening
• Frowning and anxious
• Woke and/or cried
• Nil response.
   

Results:
A high percentage of test-group fetuses had heart-rate decelerations greater than or equal to five seconds duration during the playing of the audio test tape at thirty-eight weeks gestation. This was highly significant in comparison with the test group, indicating that the daily playing of the music influenced fetal responses. At thirty-two weeks, the fetuses did not appear to distinguish between the items on the tape. However, at thirty-eight weeks the piano sonata and the choral piece elicited the most response from the test-group fetuses. The largest deceleration effect and also the highest number of fetal movements was accrued during the playing of the Beethoven sonata. The home listening had no significant influence on fetal responses during the thirty-eight week monitoring.

The babies in the test group were more ready to listen, more receptive and alert, and more active in response to the music than the control group babies were. The test-group babies listened more attentively to the piano sonata and the choral piece. They were less disturbed than the control group by the rock music (though both groups demonstrated anxiety through facial and body tension). A number of the test babies appeared to recognize the sound of the piano within the rock music, relaxing the body and facial tension during the several bars in which it appeared; the tension quickly returned when the other instruments resumed.
 

Effects of the Firstart Method of Prenatal Stimulation on Psychomotor Development:  The First Six Months

Lafuente, M. J., Grifol, R., Segerra, J., Soriano, J., Gorba, M. A., & Montesinos, A. (1997). [On-line]. Pre- & Peri-Natal Psychology Journal, 11, (3), 151–162. Abstract from: Ovid Technologies File: PsychInfo Item: 1997–30104–002.

Research Design:
Longitudinal
Control Group
N = 172
A posttest was conducted.

Purpose:
The purpose of this study was to determine the effectiveness of the Firstart prenatal stimulation method, which attempts to "advance the intellectual and physical development of the fetus by means of musical stimuli" (Lafuente et al., 1997, p. 152).

Procedure: One-hundred-seventy-two maternity patients who were enrolled in a birth preparation course participated in this study. The mothers were separated into experimental and control groups. For an average of seventy hours from about twenty-eight weeks to the end of pregnancy, the mothers in the experimental group wore small speakers attached to a waistband and connected to a tape player that played a series of eight tapes of violin sounds. After the births of their babies, all of the mothers charted the onset of their infants' behaviors from zero to six months utilizing the Observational Scale of Development.

Results: The behaviors of the experimental-group babies were significantly advanced compared to the behaviors of the control-group babies. The experimental-group babies were superior in gross and fine motor activities, linguistic development, some aspects of body-sensory coordination, and certain cognitive behaviors.