Table 4

 Association (OR point estimate, 95% CI) between pollutant concentrations in Sydney and risk of small for gestational age (SGA) for infants born in Sydney between 1998 and 2000 by exposure period

PollutantNo. of infants (SGA/total)Exposure period
One month before birthThird trimesterSecond trimesterFirst trimester
OR95% CIOR95% CIOR95% CIOR95% CI
OR estimates adjusted for: maternal age, maternal smoking, indigenous status, SES, gestational age at first antenatal visit, season of birth, and parity.
OR per 1 unit increase in pollutant concentration.
ppb, parts per billion (10−9); ppm, parts per million (10−6).
Units and averaging periods:
PM10 (μg/m3): 24 hour av
PM2.5 (μg/m3): 24 hour av
CO (ppm): 8 hour av
O3 (ppb): 1 hour max
NO2 (ppb): 1 hour max
All births
PM1013402/1380561.011.00 to to 1.0131.011.00 to to 1.02
PM2.513402/1380561.010.99 to 1.030.990.97 to to 1. 050.990.97 to 1.01
CO13402/1380561.060.98 to to 1.110.990.90 to 1.100.950.88 to 1.04
NO213402/1380561.001.00 to to to to 1.01
O313402/1380561.000.99 to to to to 1.01
5 km births
PM105391/448911.000.99 to to to to 1.02
PM2.51595/138551.010.97 to to to 1.050.990.94 to 1.04
CO2892/226841.100.96 to to to 1.250.990.86 to 1.14
NO25985/514601.071.00 to to to to 1.14
O35460/457301.010.97 to to to 1.060.990.93 to 1.03