Table 2 Characteristics of mothers and newborns delivered at Beijing Haidian Maternal and Child Health Hospital, 2006–2010
From: Ambient air pollution and adverse birth outcomes: a natural experiment study
Characteristics | Term sample (N = 47,671) | Preterm sample (N = 3,203) | ||
|---|---|---|---|---|
Male (N = 24,843) | Female (N = 22,600) | Male (N = 1,784) | Female (N = 1,387) | |
Birth weight (grams) | 3453.7 | 3331.4 | 2581.4 | 2477.2 |
(Std dev) | (415.1) | (402.8) | (523.9) | (513.6) |
Birth year % | ||||
2006 | 6.63 | 6.25 | 6.00 | 6.49 |
2007 | 23.81 | 23.99 | 21.69 | 23.22 |
2008 | 23.60 | 23.81 | 27.19 | 24.44 |
2009 | 24.97 | 24.62 | 26.23 | 25.67 |
2010 | 21.00 | 21.33 | 18.89 | 20.19 |
Household registration (Huji) % | ||||
Urban Huji of Beijing | 54.82 | 55.89 | 48.71 | 49.53 |
Rural Huji of Beijing | 1.82 | 1.84 | 1.85 | 1.95 |
Other province, urban | 27.33 | 27.44 | 26.51 | 26.03 |
Other state, rural | 15.91 | 14.73 | 22.65 | 22.42 |
Missing | 0.12 | 0.11 | 0.28 | 0.07 |
Maternal age at delivery (years) | ||||
Mean (STD) | 29.2 (3.7) | 29.2 (3.6) | 29.3 (4.2) | 29.3 (4.3) |
Parity % | ||||
1 | 87.58 | 89.99 | 80.55 | 84.21 |
2+ | 12.41 | 9.98 | 19.34 | 15.65 |
Missing | 0.02 | 0.03 | 0.11 | 0.14 |