The sound environment of the womb is very rich. There are various interpretations as to the noise level, ranging between 30 to 96 dB. (decibel being a measure of sound intensity or loudness). A whisper can register 30 dB., a normal conversation is about 60 dB. and rush hour traffic can average about 70 dB. On the other hand, shouted conversations and motorcycles reach about 100 dB. Rock music has been measured as 115 dB. and the pain threshold begins at 125 dB. Yet, recent research with hydrophones have revealed that the womb is a “relatively quiet place” (Deliege & Sloboda, 1996), something comparable to what we experience in our environment between 50 and 60 dB.

Uterine sounds form a “sound carpet” over which the mother’s voice in particular appears very distinct and which the prenate gives special attention because it is so different from its own amniotic environment. These sounds are of major importance because they establishes the first patterns of communication and bonding. Some researchers have discovered that newborns become calmer and more self-regulated when exposed to intrauterine sound (Murooka et. al 1976; DeCasper 1983; Rossner 1979).

The soothing sounds of the ocean and water are probably reminiscent of the fluid environment in which we began life. Tomatis suggests that the maternal heart beat, respiration and intestinal gurgling, all form the source for our collective attraction to the sound of surf and may have to do with our inborn sense of rhythm. Prenatal sounds form an important developmental component in prenatal life because they provide a foundation for later learning and behavior. With fetal sound stimulation the brain functions at a higher level of organization.

The ear first appears in the 3^rd week of gestation and it becomes functional by the 16^th week. The fetus begins active listening by the 24^th week. We know from ultrasound observations that the fetus hears and responds to a sound pulse starting about 16 weeks of age (Shahidullah & Hepper, 1992); this is even before the ear construction is complete. The cochlear structures of the ear appear to function by the 20^th week and mature synapses have been found between the 24^th and 28^th weeks (Pujol et al. 1991). For this reason most formal programs of prenatal stimulation are usually designed to begin during the third trimester. The sense of hearing is probably the most developed of all the senses before birth.

Four-month-old fetuses can respond in very specific ways to sound; if exposed to loud music, and their heart beat will accelerate. A Japanese study of pregnant women living near the Osaka airport had smaller babies and an inflated incidence of prematurity-arguably related to the environment of incessant loud noise. Chronic noise can also be associated with birth defects (Szmeja et al. 1979). I recently received a report from a mother who was in her 7^th month of pregnancy when she visited the zoo. In the lion’s enclosure, the animals were in process of being fed. The roar of one lion would set off another lion and the sound was so intense she had to leave the scene as the fetus reacted with a strong kick and left her feeling ill. Many years later, when the child was 7 years of age, it was found that he had a hearing deficiency in the lower-middle range. This child also reacts with fear when viewing TV programs of lions and related animals. There are numerous reports about mothers having to leave war movies and concerts because the auditory stimulus caused the fetus to become hyperactive.

Alfred Tomatis notes that the ear is “the Rome of the body” because almost all cranial nerves lead to it and therefore it is considered our most primary sense organ. Embryonically, according to him, the skin is differentiated ear, and we listen with our whole body.

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