EFFECT OF OCCUPATIONAL NOISE ON THE COURSE AND OUTCOME OF PREGNANCY

OBJECTIVES - The goal of this investigation was to examine the effects of occupational noise during pregnancy prospectively. METHODS - The e xposed group [continuous A-weighted sound level (L(Aeq (8 h))) greater than or equal to 78 dB] consisted of 111 pregnant women, and the refe rence group comprised 181 pregnant women with approximately similar wo rk conditions but without noise exposure. The noise-exposed women had more frequently other inconveniences in their work, however, like shif t work, impulse noise exposure, vibration, and a high or low temperatu re. RESULTS - With the limit of 78 dB (L(Aeq (8 h))), the course and o utcome of pregnancy did not differ between the groups. When the noise exposure was 90 dB (L(Aeq (8 h))) or more, a decline in birthweight, e ither absolute [mean 3304 (SD 585) g for the exposed versus mean 3622 (SD 548) g for the unexposed, 95% CI of mean difference -471-+15 g] or related to the gestational age {below the 10th percentile [5 of 25 (2 0%) versus 13 of 180 (7%)]}, was seen. These findings were more pronou nced if the woman was simultaneously exposed to a standing work positi on or shift work. CONCLUSIONS - Working in high noise exposure can be considered a form of risk during pregnancy.