If we think about rhythm and its different manifestations in utero, we can find it expressed in several ways. Rhythm exists in the spontaneous movements of the fetus, in intrauterine breathing movements, heart rate, sucking and kicking, in states of alertness and quiet, and partly in reaction to what is heard, for example the mother's heart, breathing variations, and activities. The shape of the human ear is a metaphor for the design and shape of the human embryo. The fetus receives sound information from the outer regions of the mother through its own auditory system. With support from touch, taste, and smell, hearing plays a prominent role in connecting us to the outside world while we are in the womb.
Hearing is naturally complex and stimulation varies when the fetus changes positions in the uterus.
Both sound vibrations and perceptions change. Sound vibration will also be affected by the location of the hipbones of the mother. This cavity will augment, by a chain of vibrations, the responses of the small bones of the middle ear of the fetus. At this gestational stage the fetal middle ear is already full size. Similarly, fetuses that are in the breech position will receive more intense intrauterine sound.