| SGA* | VSGA† | |
| Percentage increase in risk (95% confidence interval) | Percentage increase in risk (95% confidence interval) | |
| Any complication | ||
| No | 4.7 (0.6 to 9.0) | 1.5 (−6.1 to 9.7) |
| Yes | 2.2 (−6.1 to 11.3) | 12.6 (0.1 to 26.7) |
| Placental abruption | ||
| No | 4.0 (0.3 to 7.9) | 4.1 (−2.6 to 11.2) |
| Yes | 11.7 (−21.7 to 59.5) | 7.6 (−29.8 to 64.9) |
| Placenta praevia | ||
| No | 3.9 (0.2 to 7.8) | 4.1 (−2.5 to 11.2) |
| Yes | 23.2 (−20.9 to 91.9) | 3.2 (−43.0 to 86.9) |
| Pre-eclampsia | ||
| No | 4.2 (0.4 to 8.2) | 4.4 (−2.6 to 11.9) |
| Yes | 2.7 (−13.8 to 22.3) | 3.9 (−15.7 to 28.1) |
| Gestational hypertension | ||
| No | 4.3 (0.4 to 8.4) | 3.2 (−4.0 to 10.9) |
| Yes | 3.9 (−7.8 to 17.1) | 12.9 (−3.3 to 31.9) |
| Premature rupture of the membrane | ||
| No | 3.7 (−0.1 to 7.7) | 3.3 (−3.5 to 10.5) |
| Yes | 14.6 (−3.3 to 35.9) | 21.9 (−3.6 to 54.2) |
| Gestational diabetes | ||
| No | 4.6 (0.8 to 8.6) | 4.3 (−2.5 to 11.5) |
| Yes | −9.3 (−24.7 to 9.3) | 1.4 (−27.0 to 40.9) |
New Jersey Air Pollution and Adverse Birth Outcomes Study, 1999–2003 (n = 88,678).
*SGA, “small for gestational age” defined as a fetal growth ratio (ie, newborn’s birthweight divided by median birthweight 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.
Note: All risk estimates adjusted for maternal race/ethnicity, maternal education, maternal age, marital status, trimester prenatal care began, maternal alcohol use, maternal smoking, maternal drug use, percentage of population (⩾25 years) in maternal residence census tract with <12 years of education, percentage of population (⩾25 years) in maternal residence census tract with at least 4 years of college, and percentage of population in maternal residence census tract below federally defined poverty line.