Table 2.
Mean and standard deviation (SD) pollutant concentration by trimester and fetal growth category. New Jersey Air Pollution and Adverse Birth Outcomes Study. 1999-2003 (N=199,221 Term Births).
| REFERENCE BIRTHS |
SGA* BIRTHS |
VSGA† BIRTHS |
|||
|---|---|---|---|---|---|
| Mean (SD) | Mean (SD) | p-value t-test (SGA Vs. Reference) |
Mean (SD) | p-value t-test (VSGA Vs. Reference) |
|
| PM2.5 concentration (μg/m3) | |||||
| 1st Trimester | 13.8 (2.5) | 13.9 (2.5) | <0.01 | 13.9 (2.4) | 0.01 |
| 2nd Trimester | 13.8 (2.5) | 13.8 (2.5) | 0.32 | 13.9 (2.4) | 0.09 |
| 3rd Trimester | 13.7 (2.7) | 13.8 (2.7) | <0.01 | 13.8 (2.7) | <0.01 |
| SO2 concentration (ppb) | |||||
| 1st Trimester | 5.7 (2.3) | 5.8 (2.3) | 0.06 | 5.8 (2.3) | 0.33 |
| 2nd Trimester | 5.6 (2.3) | 5.6 (2.3) | 0.20 | 5.7 (2.3) | 0.01 |
| 3rd Trimester | 5.4(2.2) | 5.5 (2.2) | 0.23 | 5.5 (2.2) | 0.01 |
| NO2 concentration (ppb) | |||||
| 1st Trimester | 25.8 (8.0) | 25.9 (7.8) | 0.35 | 26.3 (7.6) | <0.01 |
| 2nd Trimester | 25.8 (8.2) | 25.9 (8.0) | 0.29 | 26.4 (7.7) | <0.01 |
| 3rd Trimester | 25.9 (8.4) | 25.9 (8.2) | 0.39 | 26.4 (7.9) | <0.01 |
| CO concentration (ppm) | |||||
| 1st Trimester | 0.925 (0.320) | 0.925 (0.322) | 0.94 | 0.918 (0.316) | 0.21 |
| 2nd Trimester | 0.935 (0.329) | 0.933 (0.331) | 0.51 | 0.933 (0.327) | 0.71 |
| 3rd Trimester | 0.946 (0.338) | 0.944 (0.341) | 0.59 | 0.950 (0.336) | 0.48 |
*
SGA = “Small for gestational age” defined as a fetal growth ratio (i.e. newborn’s birth weight divided by median birth weight of corresponding gestational age/gender/race specific stratum) ≥0.75 and <0.85.
†
VSGA = “Very small for gestational age” defined as fetal growth ratio <0.75.