Birth defects
Even more troubling is the effect that vehicle noise pollution can have on the unborn. Because the unborn are not completely protected from environmental noise, nor from their motherís response (stress) to noise pollution, they essentially react in the same manner as the rest of us. The American Academy of Pediatrics reported in a study from 1997 that "exposure to excessive noise during pregnancy may result in high frequency hearing loss in newborns, and may by associated with prematurity and intrauterine growth retardation." Loud or abrupt noises have also been found to disturb the fetus directly, causing an increase in heart rate. A most critical time in which irreversible developmental problems can occur is within the first 14-60 days after conception. Since this is when central nervous system and vital organ development is taking place, disturbances during this time can lead to birth defects and low birth weights. Studies have also shown that stress (as a product of noise pollution) causes the constriction of uterine blood vessels which supply nutrients and oxygen to a developing baby. Being deprived of these vital elements could undoubtedly lead to complications in birth.