Characteristic | Preterm birth (<37weeks) | Term (<37weeks) | *pvalue | SGA (<2 SD) | Not SGA | *pvalue |
---|---|---|---|---|---|---|
Individual level information | ||||||
n (%) | 15,615 (4.5) | 330,337 | 13,111 (3.8) | 332,626 | ||
Mean maternal age, years (SD) | 29.8 (5.7) | 29.5 (5.4) | ≤0.001 | 29.1 (5.9) | 29.5 (5.4) | ≤0.001 |
Maternal age, years % | ≤0.001 | ≤0.001 | ||||
<20 | 5.7 | 94.3 | 6.6 | 93.4 | ||
20-29 | 4.3 | 95.7 | 3.9 | 96.1 | ||
30-39 | 4.5 | 95.5 | 3.5 | 96.5 | ||
40 or more | 6.1 | 93.9 | 4.7 | 95.3 | ||
Prior preterm birth | ≤0.001 | 0.016 | ||||
Yes | 14.5 | 85.5 | 4.2 | 95.8 | ||
No | 3.8 | 96.2 | ||||
Parity % | ≤0.001 | |||||
Nulliparous women | 5.3 | 94.7 | ≤0.001 | 6.2 | 93.8 | |
Multiparous women | 3.9 | 96.1 | 2.1 | 97.9 | ||
Smoking status | ≤0.001 | |||||
Non-smoking | 4.3 | 95.7 | 3.3 | 96.7 | ||
Quit smoking during 1st trimester | 4.5 | 95.5 | 3.7 | 96.3 | ||
Smoking after 1st trimester | 5.6 | 94.4 | 7.5 | 92.5 | ||
Missing information | 8.2 | 91.8 | 3.8 | 96.2 | ||
Socioeconomic status % | ≤0.001 | ≤0.001 | ||||
Upper white collar workers | 4.0 | 96.0 | 3.2 | 96.8 | ||
Lower white collar workers | 4.5 | 95.5 | 3.6 | 96.4 | ||
Blue collar workers | 4.7 | 95.3 | 4.1 | 95.9 | ||
Othersa | 4.3 | 95.7 | 3.8 | 96.2 | ||
Missing information | 4.9 | 95.1 | 4.1 | 95.9 | ||
Year | 0.531 | 0.017 | ||||
2005 | 4.5 | 95.5 | 3.7 | 96.3 | ||
2006 | 4.7 | 95.3 | 3.6 | 96.4 | ||
2007 | 4.5 | 95.5 | 4.0 | 96.0 | ||
2008 | 4.5 | 95.5 | 3.7 | 96.3 | ||
2009 | 4.4 | 95.6 | 3.9 | 96.1 | ||
2010 | 4.5 | 95.5 | 3.8 | 96.2 | ||
Municipality level information | ||||||
Education deprivation class | 0.003 | 0.116 | ||||
High (least deprived) | 4.3 | 95.7 | 3.8 | 96.2 | ||
Intermediate | 4.6 | 95.4 | 3.9 | 96.1 | ||
Low (most deprived) | 4.6 | 95.4 | 3.7 | 96.3 | ||
Income deprivation class | ≤0.001 | 0.574 | ||||
High (least deprived) | 4.3 | 95.7 | 3.8 | 96.2 | ||
Intermediate | 4.6 | 95.4 | 3.7 | 96.3 | ||
Low (most deprived) | 4.6 | 95.4 | 3.8 | 96.2 | ||
Unemployment deprivation class | ≤0.001 | ≤0.001 | ||||
Low (least deprived) | 4.3 | 95.7 | 3.7 | 96.3 | ||
Intermediate | 4.6 | 95.4 | 3.7 | 96.3 | ||
High (most deprived) | 4.7 | 95.3 | 4.0 | 96.0 | ||
Tertiles of municipality by population size | ≤0.001 | 0.04 | ||||
First tertile (100-21,000) | 3.5 | 96.5 | 4.5 | 95.5 | ||
Second tertile (21,000-106,000) | 3.9 | 96.1 | 4.6 | 95.4 | ||
Third tertile (106,000-600,000) | 3.9 | 96.1 | 4.4 | 95.6 |